Thanks for all your replys since the on going problem been a right geek and reading how fuel tanks work etc etc. So I read somewhere that there's a fuel check valve that allows the air in the tank to vent thus allow room for more fuel. So today over lunch I left my fuel cap off and side open so the air can escape. Then went to the petrol station with my 3/4 tank which wouldn't fill fully yest and today filled with no stopping what so ever. So self diagnosed my own problem just waiting for BMW to ring me back so I can tell them how to fix my car hahaha many thanks for your help guys
