This recording is not in my collection, but I received (via Chris Webster) the following report from Grant Wilson:

I bought this at my first visit to Grim's Dyke in 1972. Inside the cassete label it says "The English Heritage Singers present for your enjoyment a collection of some of the finest duets, trios and quartets from the music of Gilbert & Sullivan. Over the years we hae had much pleasure in performing these pasterpieces to mnyof the Livery Companies of London, and soirees throughout the country."

When I was at Grim's Dyke, it was on a Sunday evening, and the then owners used to present a dinner show. The audience would go into the dining room, where this group, plus a couple of local artists, would entertain for a few minutes. Everyone would then have their appetizer. The group entertained again, followed by all having their main course. The group entertained again, after which all had dessert and coffee (or whatever).

Then the group entertained for a fair amount of time, including as I recall some requests. Then they had a sing song in which the whole audience took part. At the end they played/sang "Dance a Cachucha" when the group would pick audience members to dance with them, and then change to other audience members -- a riotus ending!

I have been to Grim's Dyke three times, and although the first two times were as above, the third time there was no sina-a-long or dance, and I am now given to understand this Sunday evening ritual no longer takes place. The cassette includes selections from Mikado, Utopia, Patience, Pinafore, Yeomen, Iolanthe, Ruddigore and Gondoliers. Nice background music/singing.