I'd heard that story, too, Bert. I've just tried to verify it. Looked at the George Formby Information Service at:
http://users.powernet.co.uk/lampost and the banjo-ukelele site at:
http://freespace.virgin.net/dennis.taylor
It is clear he had a lot of banjo-ukes(some of which fetched high prices at auction later) but didn't confirm or disprove the story. There are several more fan-sites but don't have time to pursue them!
RtS