thanks for the oil level suggestion. Unfortunately not that simple! Local garage (not a vauxhall agent) had a look and plugged it into their magic machine. No answers. They think it might be a relay...
I have an Astra Club automatic, 1999, little used with only 3000+ miles. It has recently stuck in 4th, although will change ok if I select 1-2-3-D using the stick. any pointers? thanks...