The Beach Store was actually Situated underneath the seafront flats referred to above, it was closed when the flats were rebuilt and renovated in the late seventies I believe.
Bubblyrat, your memory is I think slightly askew, Whilst the Black horse did host some activity during the 60's and 70's it was never one of the major venues, I think what you are remembering is the Horse and Groom which was immediately behind The Swan, and is now a terrace of houses, many official sessions were held in the Skittle Alley there, and the garden and small front bars were always a centre for unofficial song and music activities.

Henry Piper Old Father Christmas, Sidmouth Traditional Mummers.