Strange problem with instrument cluster

Hi there, I'm just asking to see if anyone has encountered a similar problem to mine with my Roomster (and might have a better clue than me! ). What happens is:

(1) after keying engine off, panel goes off (as it should), then after about 5 secs, pointers light and fuel gauge shows true fuel level, also airbag and engine light shows

(2) if I take the key out, I get "key not found" error message in centre of instrument panel

(3) if I leave the car and lock using key button, panel starts flashing all sorts of warning lights and backlight/pointers flash.

Any ideas gratefully received....thanks!