Hi Sue, Thanks for your lengthy reply.
Minty's hearing isn't great. I have been making noises that I know she reacts too - banging, whistling, weird noises - but I know that they need to be loud. She is hearing them though, but her hearing hasn't been great for a long while. She often doesn't know where the noise is coming from and looks in the opposite direction to where the noise is. Her eyes aren't the best, although she can see long distances, her vision is narrow. You need to be in front of her for her to see you as she seemingly has no peripheral vision.
Minty is a very affectionate cat. She doesn't come to you apart from at night, you have to go to her, but loves it when you do and will cuddle in with me. She may have had another seizure without us knowing. I guess I hadn't thought of it, as unlike the other two nobody has seen it and she hasn't been pacing around afterwards.
It's funny you mention Hyperthyroidism as I have the human variety. She's a yowler anyway, she likes to know someone is there, which isn't always possible, but I imagine she's never alone for more than 3-4 hours at a time. I think she was very slightly sick yesterday, but nothing else. She always has a big appetite, but usually clears a plate quickly. She hasn't lost any weight I would imagine - she's still a big lump! I'll try some dry food at night again, a mixture of wet and dry as she likes both, but prefers wet.
I don't mind carrying her at all - she can do it, I just do it to try and help her. I thought I would ask as I may have been taking away her freedom or similar. I'll look into those steps. Are they really easy for a cat. Would she realise what they were for?
She literally has two places she spends all of her time (aside food and litter) and that's her corner on the sofa (she won't go anywhere else on it) and my bed. She appears to feel safe there. If she makes it, she's 20 in October. Even though I know time is precious, she's a cat that just bounces back. I know one day she won't.
Everyone thinks she's spoilt because I buy her meat from the Deli etc. I agree she's just cared for and loved. It seems to have worked as she's nearly 20. Some people don't understand though.
I feared it may be the vet. She's sick on journeys and it's not my car. So stress for her, stress for me. I'll contact him and ask.
I know time is short now, but we've had great times together for the last near on 20 years. I guess I feel sad and teary thinking about it and i'm going to be completely lost when i've lost my final baby. I guess it annoys me that most people that I know just don't understand and that she's 'only a cat' or work thinking it's not a good enough reason not to be available for overtime as they all have 'families' and should therefore get priority over holidays, days off and Christmas hours etc.
I've called in sick today as I feel rough myself and little sleep hasn't helped. I will have to go in tomorrow though. Only 6 hours and 1/2 hour lunch means I get to come home for 10 minutes as I don't work far away. I can check her and make sure she's ok and freshly fed. Partner and flat mate are both away assisting on a summer camp until tomorrow night.
Thanks again for your response - I will respond to others now - and thanks for your link to the chair, below.
Miroslav, there are a few things which occur to me here about Minty, any of which could be the cause of her behavioural change, but let's just explore whether you think any of these may be an option.
When we had Paddy, who lived until he was just over twenty, he experienced a stroke at the age of 15.
As a result, he was left deaf, and it distressed him at first until he got used to the change. He would seek us out much more, and cry.
He had never enjoyed being picked up, but as these changes occurred, he more and more wanted to be with us, to have us near, and to be cuddled. It's possible Minty may have had another seizure you're not aware of, and it may have left her feeling confused and distressed. Paddy used to pace restlessly - almost as if he couldnt quite settle. If he wasn't pacing, he was sleeping.
Paddy also developed hyperthyroidism. It's quite common in elderly cats, and can also lead to yowling in cats that haven't exhibited that behaviour before - especially at night, for some reason. It may be worth asking your vet to specifically check for Hyperthyroidism. It would normally affect their appetite too, and can lead to increased vomiting, weight loss - especially round the hindquarters, or eating little and often, so hence repeated requests for food. The food often needs to be fresh to tempt their appetite, so food left out overnight wouldn't necessarily satisfy her (unless it's dried food, and she's accustomed to free feeding)
I wouldnt stop carrying her up and downstairs, if you dont mind doing it - it gives her much needed contact with you, and will help her access her old familiar places, which she might otherwise struggle to do on her own. I suspect her not jumping on the bed may have more to do with age and agility (or lack of it). You can get small cat steps from somewhere like the cat gallery (online) and these can be placed at one side of the bed to allow her to access the height more easily.
I dont think she's "whinging" as such, I think it's more likely to be physical changes which are affecting her. 19 years is an excellent age for a cat, but in human years she's almost a centenarian. If she's feeling poorly she may purr. It's long been thought that a cat's purr has a healing vibration which helps comfort a cat in discomfort, so can be used to help them feel better when in pain, just as much as being an expression of pleasure when they're happy. If she's purring when she has her face tucked in to the sofa, this may also be an indication that she's in pain. Cats hide it very well - as prey animals, they have to.
You clearly love Minty very much, and she loves you. I wouldnt say she's spoilt - I'd say she's been beautifully cared for - there's a difference. 
The fact you're not feeling so good yourself won't be helping matters, as you'll need your rest and a good night's sleep. It's probably worth a call to your vet, to talk through Minty's behavioural changes and asking if they think it's worth testing her for HyperT, or to see if there is anything else which may have changed since her last check up. Often, your vet may be able to detect physical changes in the thyroid gland just by feeling it. Alternatively he may feel blood tests are sensible.
The time that you and Minty have left with each other is very precious. She won't be doing anything deliberately to "annoy" you. She's only reacting to the age induced changes, which may be impacting her health in ways which aren't immediately obvious. Elderly cats can be very demanding, but they're worth it. Their health issues can keep us on our toes, and that's not always easy when you're not feeling great yourself, but I hope that you and Minty will continue to enjoy and benefit from each other's company for however long is left to Minty.
