I have a set of volumes titled AIRCRAFT OF THE FIGHTING POWERS
dated 1939 to 1945.
One of them has plans and photographs for the WESTLAND WELKIN.
Now the sad bit, I know one of the volumes had the same on the WHiIRLWIND, I remeber looking at them.
I mentioned these books on another aviation website and a punter expressed a great interest, so Drapes being a generous cove packed up and sent him one volume,to somewhere in France no less, never heard another peep, so I had no idea if he had recieved same or it had gone adrift, so I hung on to the other four volumes.
You guessed it the volume that has vanished is the one with the details of the WHIRLWIND.
The 1945 edition does have as I said details of the WHELKIN.
ps, If your organisation is interested these books contain as far as I can see drawings plans photographsand details of every aircraft of the second world war period, they will only finish up in a skip when Drapes pops his cloggs so if you drop me a line you may certainly have them .