You can easily find a JCM800 for £500 on ebay :? Master volume JMPs are great and cheap(ish) too. Certainly under £500 anyway. If you want clean and high gain tight sound I'd look for a 100W one. More headroom and tighter gain. Oh also, don't be thinking that 2210 has a clean channel. It just has a normal channel and a boosted channel.
Personally, I think you'd be better off with an old Mesa. Or a MkIV if you can afford (and find) one.