In that case, GF, try Elstree aerodrome - get the train from Kings Cross Thameslink to Elstree, then it's a walk or a taxi to the airfield. There are a couple of schools there - the big one is Cabair, but do a search and read up on their reputation before signing up, or else try Firecrest.
According to
the school's website, Stapleford airfield is a bus-ride away from Romford train station, on the Liverpool St line. I know very little about them, but they do offer CPL training which might be a positive factor for you?
FFF
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