Thanks to all who replied.
I bid the manufactured 2
♦ reverse rather than a more prosaic (albeit sensible) 3NT, partly because I wanted more information and partly because I feared a diamonds lead.
I confess that my main reason for posting was to seek confirmation that 3
♣ would have been a clear underbid, as I felt but others did not.
But it's useful to see how much support 3NT has.
FWIW here is the actual layout and auction:
Only 12 out of 106 found the diamonds lead on either side (even without the semi-psychic reverse).
And only 10 bid and made 4
♥ (rank one up to the Norwegians).
+++++++++++++++++++
A 1♣ opener is OK because this is seems too strong for a 1N opener. Now I rank rebids as
1. 3N = NAT Good clubs, good hand.
2. 2♦ = Manufactured reverse.
3. 3♣= INV Underbid.