Well OTL, the UK (along w Denmark, Ireland, and Norway) looked to join the EEC in 1960, only to be vetoed by DeGaulle. They did not resubmit until 1967, which happened just in time to see DeGaulle leave at the right moment, lifting the veto.
How all this is affected by a DeGaulle assassination in 1962 -- I'm afraid I don't know enough about EEC political mechanics to know...