Yeah, timing belt spec on these is 4 years, 48,000 miles. As timing belts go, its not a difficult job because the engine is round the 'correct' way and so you can pretty well get at everything you need to without major dismantling. However, if you don't get everything lined up properly then the engine won't start again, so if you feel unsure probably best to leave it to someone else, and for that price, its not bad at all. What I would do though, is ask them to use proper Volvo parts. If they're reluctant then you go and buy them at the dealer. The genuine belt I think you get change from 10 quid and I think the tensioner was about 30 quid. The genuine belt was cheaper than I got quoted at the motor factor
It probably needs a good run and then a tune up and then see what's going on. The injectors will be a little sticky from all the non-use, and the valves too, but they should clean up in time.
The plastic cups for the inside door handle....rare as hen's teeth to find one that's not damaged or cracked I'm afraid. Its a case of scouring scrappys and auto-jumbles.