The mainstay of BSA's war effort had been the M20 dispatch rider's bike which had proved its worth throughout the conflict, and gained a consequent following back in civilian life for many ex-servicemen. Both the M20 and its larger sibling, the M21, had been introduced before the war, but the vast majority of WD machines had been the smaller 500cc M20 model. Reintroduced post-war in 1946, the M21 continued for many years as a sidecar bike in the BSA range and, perhaps, its most iconic iteration was as the ubiquitous AA patrolman's outfit, pulling its bright yellow sidecar, filled with all manner of tools to be utilised by the AA man in getting your broken-down vehicle back onto the road.
Whilst some AA outfits have been 'made up' over the years, RSK 606 (originally registered UYO 77) started life as an AA machine, as evidenced by the entry in the RF60 log book listing the first owner as 'The Automobile Association'. Purchased by the deceased owner in good running condition in 1983, it appears to have been used, to some extent, until 1996. Having been standing since that time, it will now require some degree of re-commissioning or restoration, depending on the buyer's preferences. Documentation accompanying the M21 comprises a current V5C, an old V5C, old V5, the aforementioned RF60 buff log book, 12 expired MoT certificates, 2 expired tax discs, and miscellaneous papers.