Problem with Greddy Auto Timer - wo else has one?

[M@r]{]

This has never worked properly since fitting.  It either lets the engine shut off imediately or doesnt complete the count down.   Every now and then it does do the count down ok but rarely.

Any ideas?  Is there anyone/where I can get the unit looked at?  Or would it be more cost effective to just buy a new one? (£70ish)