Bust timing chain on a class - ditch/repair?

[MmeButterfly]

Hi all - i really need some help making this decision - i've only had my lovely a class since september and it basically died the other day after a few days of dodgy starting. The mechanic says the timing chain has broken and this has in turn broken some valves. He says that it needs a new engine and he has sourced one. The whole thing will cost me £800 - i just don't know whether to do it or just start looking for a new one.
Its a 2001 model and i think i read something on the net about these having this problem sometimes. Any advice??