... the following are just delvings into a memory that is quite a bit past its best, but as I remember Jack Hearne Cycles was based either in the suburbs of London or slightly outside in leafier Hertfordshire. I seem to remember his adverts in one of the "go faster racing " magazines that we read back in the 50/60s. As I recall he imported or distributed quite a range of continental frames - or was that Hearneville Cycles(?) - and the business was sold on and changed its name. Whether or not Jack made his own frames - often time-trial frames - or had them built by one of the many jobbing builders working in the area at that time I couldn't really say. All of which I suppose doesn't add up to very much concrete info.
If one of the southern-based folks from London or Surrey etc don't come up with more info, I'll go root out the old mags. I'm more of a northern man...
Norris Lockley