This is one of a series of increasingly tenuous, easy caches celebrating Rickmansworth's musical connections.
Andrew Ridgeley, 50% of Wham!, used to own an upstairs bar in the High Street. It's now part of a pizza restaurant.
Magnetic nano - you'll need a pen, and some extreme stealth - very muggly, maybe best done at night. Parking is available, but can be hard to come by in the daytime.