I suppose this counts as Classic because men were racing on beaches before tarmac circuits were built. At the first Wallasey meeting of the year some road racers entered their bikes to try them out. We had a lot of fun, the spectators did too and for free, the west coast usually went right handed, Wallasey, Ainsdale, Pilling. The east coast left handed, just move the sidecar wheel up and back, at Hartlepool, Redcar, Saltburn( a long established venue for record breaking), and Filey with a seawall for good spectator viewing. The straights were half a mile long so you couldn`t see both ends on a flat beach. Actually Wallasey wasn`t flat ,it had channels where the tidal pools flowed back to the sea and at 100 mph on a rigid frame it gave you quite a jolt.
The first time we went to Wallasey in 1967 there were 52 sidecar entries, 4 races of 25 crews in each and whatever survived the grit and sal$%^er in 1 race at the end. Then you had to race the tide to get all your stuff off the beach!
I`ll see how much interest I get and post some more later.