We've just bought her a 5 door because of a new baby so the Corsa is currently sitting idle.

I reckon it's worth circa £700 despite its age. Here's why:
84,000 mile on the clock. Had a brand new engine at 45k so this engine has only done 40k.
2 lady owners from new (including the missus)
Has been serviced every year (we have the history)
It's in good condition, starts first time everytime and is a reliable runner
MOT'd until May 2013
Other details:
16v
Electric windows/mirrors
Central locking
CD/radio
Pretty minor faults include:
The sunroof needs a new clip although it works and doesn't leak at all.
The left front speaker doesn't work.
Other than that it's a great example and it's in it's original condition (no mods or silly body trims).
Clean and tidy too.