Hi Sandman - No, I hadn't thought of contacting Donovan because I don't remember him being around Soho that early. I became aware of him later in the 60s. Maybe I just missed him!
But it might be worth a try. I wouldn't want you to give his phone number and address out without his permission. Maybe you could check with him if he was, indeed, around Soho in the 50s/early 60s and if so if he wouldn't mind me contacting him.

Thanks for you help.

Best- Dave