As already mentioned, revision guides.
The new edition tailored for the new spec has been released by CGP, so you could try those.
In regards to Computer Science, i'm not the most informed so I can't help much there, but with physics, there isn't actually too much that has changed in the syllabus.
They've taken out a few things, added a few things, but on the whole, most stuff is the same.
If you want questions, I'd suggest the website 'Isaac Physics'. They've got a good 400+ question spread across AS and A2.
Revision guide questions, which do provide answers (CGP, Heineman) or the offical textbook which contain summary and exam-style questions or past paper.
Putting aside any specimen papers that there may be, I would still strongly encourage you to just do a normal past paper, leaving out the stuff that isn't in the syllabus this year and then just search for questions online relating to the additional content for the new syllabus, if you don't want to use Isaac Physics or revision guides/text books.