There is one of the old school type spares/surplus shops in Lincoln. Can't now remember what it's called and I think it's highly unlikely they have an internet prescence. Seems to be run by quite an elderley fella with help from mates. I was, and still am, looking for a 4 way GPO type jack plug. They had a 3 way attached to something, closest I've come to seeing one in years. There's loads of ex aircraft dials and such on display in the window, wouldn't be totally surprised if they had a bomb release panel in a backroom
It's on the hill on the way from the station to the cathedral, the narrow street is called The Strait. It's nearly opposite B & H models who do have an extensive railway range.