I have a friends birthday to go to and I have to go to scotland to met mygirlfriends mother for the first time which should I do, the party or the trip to scotland, and I have already spent £60 on flights but the party will probably be more fun?

How serious are you about your girlfriend? How long have you been together? Is girlfriend's mother expecting to meet you and have special plans already been made for the occasion? Is this someone you plan on having a long relationship with, possibly marrying someday? Would the girlfriend skip out on the trip to Scotland to go to the party with you? (At least then, it would be you both skipping out on mom!)

If this is the "Kleenex" variety (throw it away, another will pop up) relationship where you are not serious and could really care less about meeting her relatives, live it up, go to the party. But if you plan on making this relationship work, go to Scotland, especially if this is a specially planned trip. It would be rude to skip out just for a night of fun and would show your girlfriend and her family where your priorities are.