@Fred, ah yes, Edgware Road. It was Henrys that I visited a few times and seemed to be served by a chap who looked like my elderly maths teacher. He seemed civil enough so perhaps I was ill-informed. I’d been told to ask for ‘transmitting’ capacitors and I felt he was reading me for clues. I’m pretty sure I went to Lee Electronics to not find things there too. I moved to FM after this, it seemed simpler and the battery lasted longer.