Responses
I think it’s to create an identity for himself and if Jin was there it would hold him back as he’d want to be with him the whole time. Also I don’t think the organization would like him going on a spontaneous vacation all of a sudden. They’d find it fishy.
Author just wanted to give us more plot
Maybe I’m old fashioned but since he also just quit his job, why mathew didn’t invite jin to come with him to england? He surely could start working there and after his education they could return together