Hello Hock. Welcome to Purrs! You'll like it here I think. There's loads of good advice and friendly people to help out with questions and guidance. Marvin sounds great. Glad to see you've been able to provide a home to a more mature gent.
With regard to a cat flap, Staywell do ones for glazed doors, and they're probably one of the easiest to fit, although if you don't fancy cutting glass etc, a glazier will do it cheaply enough for you. I think the magnetic ones are a good idea if you do have a problem with strays, but it's rare.
We have two cat flaps fitted - one to the external door, and one to the internal. Both are multiway locking, so we can schoose whether to lock the flap so Paddy can come in only, or go out only or not go out at all eg when firework time arrives. The reason I had two fitted was not only ease of access for our cat, but also, in the event any strays were caught out when firework time comes round, they can access safety through the first door, without necessarily gaining entrance to the main house through the second. Bit elaborate, I know, but it suits the purpose!
I would definitely recommend pet insurance whatever the age of your pet, and there are many more pet insurers now offering insurance for senior cats and dogs. Shop around and see what's available and what types and level of cover you can find - some insurers only insure you against a specific claim limit, others for the duration of the illness, so its better going for the latter where you can afford it.
As he's an older cat, he probably won't be so inclined to scratch, although you can never be sure (Paddy still likes to scratch the carpet at the top of our stairs, and he's sixteen and a bit!) I would put a large throw or blanket over the sseats and the arms until you see whether he's inclined to scratch or not.
We use Frontline for fleas which is a spot-on treatment, but it's as well to let your vet have a quick check of Marvin before using it first time. You can buy spot-on treatments from your vet, although they can be a lot more expensive than buying online. Paddy gets his done about every two months (sometimes alittle longer if we forget!) You'll need to check initially just to make sure he doesn't have any skin irritation, and don't put it where he can lick it off (back of the neck is normally the best place to apply it)
We get Paddy wormed at the vets about twice a year(he goes every couple of months or so as he has some long term health problems) and it's easier for us that way as he doesn't take to tablets at all well, but again, your vet can advise which method he thinks may be best if Marvin is a tablet spitter-outer (as you can get liquid wormer). If he'll take tablets, then you can give these yourself. You work out the dosage according to bodyweight normally.
There'll be other suggestions for you too, so sing out if you need any more advice or help. We'll look forward to seeing piccies of Marvin when you get him home.
