Yes I don't think bikes, nor much else used to move very far before the advent of the national "trader" papers and now the internet of course.
I did once buy a little bike from a local and very senior fellow, who told me how he used to have Vincents put on a train from London for collection at North Walsham Station in Norfolk. They were advertised in one of the national papers. Presumably during the sixties.
The Norfolk pre-fix was AH I think.
Yes could be Kent.. Just as bleak as N Norfolk..