I did ask my brief, what if they discover I'm lying, and he said ............
"Just tell them I told you to say that, the judge might tell me off, but he and I will still be having lunch and drinks together in the pub after the case"
But saying you don't remember can't be proven as a lie, I can't even remember what I had for breakfast yesterday, and if I were a Prince, one more shag in a sea of shags probably isn't any more memorable to him than yesterdays breakfast is to me.
Andrew has the right to 'due process' and should be considered innocent until proven guilty in court.
(Not that i'm sure a Prince is answerable to a civilian court)