The Answers
1. what a/c sim is used - what ever you want to fly, A330 or B777 sometimes the A310, depends a little bit on your own CV, experience on any of these A/Cs
2. do they still show you the apartments- yes they do, the best one they can show you at this moment. So expect a lttle bit worse than the one you have seen.
3. present salary - good question, simple to say too less for Dubai
4. what books would be useful to gen up on company info - no books required.
5. technical exam info (is there a book for it) - ATP stuff
finally do i need a visa for attending the interview - did you read your email already from HR? They will arrange the visa if you need one, however you come from UK, so you get a stamp in your passport, thats all.