28 January 2007, Roger Harper stated the following in an email:
"I believe the grotto is the Ice house where ice was made and stored for the estate, I know this as in 1975 I purchased the Turnpike cottage in St Arvans, and my Neighbour Mr
Tom Stephens who then was in his 80's lived in the house next to the
village hall. And as a boy and young man worked for the estate and
house at the turn of the Century (1900) we had many walks around the
mansion and grounds and he explained and pointed out to me most of
the aspects of the house and gardens that he had fond memories of."