You may be right about copyright, I know that his wife was still looking after the estate and still giving talks about him up to two years ago.
I listened to the Oxford Union recording yesterday which features the original monologue on which 'Murphy annd the Bricks' was based. His delivery and timing still make me laugh after about 50 years, and his concluding serious remarks about the government of the day ans Arts funding still apply. A truly great guy!

FC