Are you sure it was '72? I had it down for the '70 tour( I could be wrong on this). It was also my first ever live gig. The majority of the audience was to the side/behind the stage (me included)and I think this threw him. I don't recall the shaving quip. However, I have a vivid memory of his encore: a chorus of ' it wasn't very good, there's no reason why you should, remember me; and spoken verses that recalled various situations in which he had fallen short of his own high standards. The only verse I can vaguely remember recounted an amorous encounter with a lady that failed to fulfill its promise.
If it was '72, this means I have missed two of his tours!
Manchester 17th June, Edinburgh, London RAH 18th, Manchester MEN