For example CAE Oxford have arrangements so that their students can obtain a licence issued by the UK CAA or Belgian CAA or Spanish Authority. No doubts the other ‘big 2’ have got a similar way out
CAE always had ATO approvals from other States though and I don't think this facility is Brexit related - used to be a function of where you started training and therefore place of medical issue. Regarding TK Credits, examination result notifications explicitly state that they are pertinent to 'EASA Part - FCL' as well as the licence type the examination was for. I can't see that this could be contested provided the UK was an EASA member at the time of the credit.