If one person has expressed the wish to own a record and several others have said that it is a nice tune, does that qualify a raise in price?
You admit yourself that you haven't sold a UK copy in a while and that you have one filed - surely this means the demand is low?
In my opinion this means your 'price guide' is of no value, as you may just change your mind of a records value at any given time?
BTW There was a whistling man to indicate the joke...