The 18-carat gold, fully-functional toilet was part of an exhibition by the Italian conceptual artist Maurizio Cattelan.
Members of the public booked slots to use the toilet in its cubicle.
Mr Jones told the court that, during his booked slot with the golden toilet, he did make use of it.
Crispin Aylett KC, defence counsel for Mr Doe, asked Mr Jones “What was it like?”. Mr Jones replied “Splendid.”
A fourth man, James Sheen, 40, from Wellingborough in Northamptonshire, has previously pleaded guilty to burglary.
Mr Jones told the court he was friends with Sheen and that he worked as a roofer and general builder for Sheen’s building firm.
During his evidence he said that messages and voice notes between the two of them around the time of the heist were work-related or about a large dog kennel he was planning to help Sheen collect from Milton Keynes immediately after his visit to the exhibition.
He denied that his two visits to the palace in the days before the raid were as reconnaissance for the robbery.
He told the jury he went to the palace on 7 September to see a car show and again on the 13 September to see the exhibition.
