I was recently lucky enough to meet an old gent with 2 Harry Quinn's he and his wife had raced. He knew Harry well and had both bikes made to measure and built by Harry Quinn. He also had a tandem built later when Harry had moved to South Wales, Tenby I believe.
Unfortunately, as has been said above, Frank Clements bought the name and basically used it to badge up some very mediocre frames and sell them off for a quick profit. If it doesn't have the 'Q' serial number, then in reality its not a Quinn frame.
I've also seen one of the last Harry Quinn frames which were hyped up as the 'last available Quinn frames'. Still in bubble wrap and never been built up. A horrible piece of Reynolds 501 kindly badged up care of Clements. However, the owner is convinced his sat on a unique piece of cycling history and expects around £500 for it