The Parkzone T-28 Trojan costs about 190 pounds http://www.sussex-model-centre.co.uk...d.asp?id=23818 I've seen them fly and they do very well. Both people who own them are using them as a second plane after learning to fly using electric trainers.

Edited to take out the "weight" implication and to add:

In RCKen's "Looking for a Trainer?" thread http://www.rcuniverse.com/forum/m_4537845/tm.htm he included a "second planes" listing.
All are glow powered. A few are RTF, most are ARF, and a few are kits. You can see which ones are available in the UK and which ones fit your budget. I'm pretty sure all will cost more than the T-28.