Richard Briers?
I've just noticed that Richard Briers is on the cast list but having just watched the film I don't remember ever seeing him on screen. If I missed him it couldn't have lasted more than a few seconds.
shareYou can (very) briefly see him at the beginning sat at the dinner table when they perform the underground song. He's Peter's father, as in when Sarah says something like "I don't know why your father hired us if he and his friends weren't going to laugh". I've always assumed his scenes must have been edited out for some reason.
"Of some delights, I believe a little goes a long way"