For £200, I'd most certainly be looking at the second-hand market as you'll struggle to get a good new amplifier for that cost.
Perhaps a second hand Behringer stack? I owned one for a while and had no problems with it whatsoever. I also found that it had quite a usable tone for the money.
Something like [url="http://cgi.ebay.co.uk/BEHRINGER-ULTRA-BASS-BB115-1x15-SPEAKER-CABINET_W0QQitemZ220488124865QQcmdZViewItemQQptZUK_ConElec_SpeakersPASystems_RL?hash=item33561dc9c1&_trksid=p3286.c0.m14"]THIS[/url] coupled with one of [url="http://cgi.ebay.co.uk/BEHRINGER-Ultrabass-BX4500H-450W-Bass-Amp-Head-NEW_W0QQitemZ390096635513QQcmdZViewItemQQptZUK_MusicalInstr_Amplifiers_RL?hash=item5ad3924679&_trksid=p3286.c0.m14"]THESE[/url] (if you can get one second hand, that's a new example)
Hope this helps you out - there are a lot more options out there for under £200, it's just a case of keeping your eyes peeled for the right combination of value vs tone.
Danny