Update:-
So I downloaded the transfer form as above, and made all the copies asked for, for self and wife, plus the VFS Global paperwork, and took the whole lot to Jomtien.
No queue ticket was required, go straight to desk 8, where I was greeted with a friendly smile. "Two passports?". "Yes".
The officer looked through the paperwork, threw back the VFS stuff as irrelevant, gave me two tickets. "Collect them tomorrow after 1:00". Which I did.
In an abundance of caution, after collecting them, I did online TM30s for myself and my wife under the new passport number, which were accepted by the system. I did a screenprint of the result, to put in the passports by way of proof.
I should add that before I went to Jomtien I did our 90days online, due in a fortnight, under the old passport numbers.