Hi Ed

This is what I would do but I am prepared to be corrected by a more qualified director

If its in your system card on the table suggest the opponents refer to that

Otherwise

Don't say anything but call the director and explain the situation away from the table

And if I was the director I would take your partner away from the table and have you explain the situation to your opponents only.

Of course both you and your partner need to avoid making use of any UI, (which is inevitible in this situation whatever you do). That means you both must continue bidding as if your own version of your system was the correct one. At least until one of you makes a bid which is "impossible"

National Director(s): comments please

Nick

Thank for your reply Nick

You say:

Of course both you and your partner need to avoid making use of any UI, (which is inevitible in this situation whatever you do). That means you both must continue bidding as if your own version of your system was the correct one. At least until one of you makes a bid which is "impossible"

I know that the 2D bid is saying spades because of the incorrect explanation and understanding of the system. Technically, by the correct version of our system 2D shows a 5 card diamond suit. So with 2+ diamonds (which I had) I should pass or choose 2NT. But I know the hand does not have 5 diamonds but does have 4 spades via the incorrect bidding. So in this instance would I have been okay to bid 2H (showing spades in puppet stayman)? Or am I ethically bound to pass (as per the proper system) leaving us in a 3-3 fit? For the record I bid 2NT.

"I know that the 2D bid is saying spades"
That knowledge is unauthorised

So you must bid as if partner had shown 5 diamonds (which would be either pass or 2NT (or 3NT?) depending on your strength and your diamond holding)

Sure you will get a poor result playing in a 3-3 diamond fit with a 4-4 spade fit on the side 
Thats often what happens when your side makes a mistake.

That's what I thought. As I had the Ace of Hearts among my 10HCP I thought I was ethically and legally fine to bid 2NT. As both a player and director I always find this area of the laws the most difficult to fully grasp. Thanks for the clarification Nick.