Not sure exactly how old you are, but "single seizure clinics" have proliferated in The UK of late. If you were referred there, it would be handy to get hold of those notes, as it's likely you would have seen paediatrician who has some specialisation in the area.
"Seizure" can be a bit of a wishy washy term, especially if "diagnosed" in Primary Care.
Either way, I think you probably need to get the whole episode unpicked by an expert, prior to your medical.