Morecambe and Wise + Jack Benny

I am convinced I saw an episode of the Morecambe and Wise Show from the early 70s where Jack Benny, on one of his tours of England, guested and did a short stand up routine where he talked about "the guarding of the change". I cant find a record of this on IMDB under either Morecambe and Wise or Jack Benny. Does anyone else out there remember this, or can they present enough facts to convince me that it did not come from Morecambe and Wise but from some other British show of the time?