It is for this reason I would have bid 2NT/2♠. I agree, mostly so partner can rebid 3♣ if he has them. Seems to me a 2NT call over 2♠ should deny a useful side suit. How do you ever find your ♦ slam? Partner hasn't passed out 2NT yet so we won't miss a 5-4 diamond fit. If your main priority is finding a 5-3 diamond slam from responder's side with his Kxxxx, you need to reexamine your priorities. Maybe I asked the wrong question. Seems a number of you prefer 2NT vs 3♦ as a rebid. I confess it never occured to me at the table ( I need 2♠ for that bid ), can't say that I see any compelling reason to feel different now!. Admittedly 3NT seems the better call over 3♠. Thankyou for the response.