It's sad to hear about your cats and the situation you're in. Have you tried rescue centres in the local area? (I presume you have, but it's always worth keeping on at it!) I would also ask in local vets and get them to put up a poster for you.
I do have a friend who lives in the Bradford area who has recently moved to a new home near a busy road and has had to leave her cat at her mums and she is now looking for an indoor cat, but would consider taking on two. She lives in a rented property, but would be able to get written permission about keeping cats. She has had indoor cats before and therefore is well versed in preventing potential escapees! There's only one entrance and that's a double one with a porch which is good. There are no other pets and no children in the house and she is looking for fun, friendly and playful cats. She doesn't have too much experience of timid cats and therefore wouldn't want to take on anything too timid.
I can pass on contact details for you if you want a chat with her?
She's tried local rescues in her area (there are only two really and one is atrocious), and so asked me to keep my eyes open for something.
Just let me know what you think,
Jen x