Skattyskoo

I have a 2008 (May) Astra 1.6sxi with about 74,000 on the clock. Recently when driving around a large roundabout in 3rd doing between 30-40mph the engine light came on for a few seconds. I told my partner and he said a few lights have come on and gone off again when he's driven it too: the engine light, oil light and the one with the exclamation mark in. It was serviced back in May and I haven't been doing as many miles in it as I used to, it's probably done 6,000 since then. I've checked the oil and so has my partner and both times it's been fine. Anyone had this problem? Also just out of curiosity, if my car was in perfect working order, how much do you think it's worth? I'm coming to the end of my loan and thinking of getting something else. Thanks in advance!