Just to add my tuppence worth. If the OP is looking for an amp that he'll keep for a few years, it's unlikely he'll be disappointed with any of the suggestions. The only slight caution is that they will have slight tonal differences, this will determine the speakers that'll optomise the amps qualities.
If the OP plumps for MS 908s, for instance, I'd be looking at smoother amplification such as Marantz, Arcam... I'd avoid Yamaha and Cambridge with those particular speakers: A friend used to have Cambridge 640 amp/CDP with MS 914 and found it to be too bright.
However, in isolation, and with the right speakers, you should be chuffed whichever amp you go for.
Ah right okay, and as for value for money, how would you say £200 is?
Any of the aforementioned suggestions would be great VFM. However, if you go for Yamaha or Cambridge you'll be hard pushed IMHO to beat these:
http://www.richersounds.com/product/standmount-speakers/wharfedale/diamond-10.1/whar-10.1-blk Or if you look at floorstanders look at Wharfedale Diamond 9.4 or 10.4.
Those wharfedale speakers are a great deal! My issue with the MS908s is that I can find very little information for me to assess a rough value on them as they're not very common speakers
If you have room them they seem like a solid purchase.
Great and thanks for all the information, I think I'll take the guy up on the offer of £200 plus fuel for the CA 640a V2 and MS908's and tell you how it goes. Perhaps maybe offer him a bit less if that's not a bit too cheeky?