Excuse me!
At 8.45am this morning I called the number provided to contact the MFA directly. Press 9 for English.
At 8.48am this morning it was answered by a very polite lady. I explained the problem of registering on the expatvac website successfully then receiving a notification that it was being rejected because of wrong visa. (As many have reported).
She assured me that within 2-3 days I would be sent a link to edit my document and re-submit.
She explained that the problem with the submittal form only accepting one form was basically my fault and (sort of) advised that the 'visa' and passport copy should be on a single form. Ok, not going to argue. She never asked for any I.D. to check, so I assume everyone who received the 'successful registration' followed by the 'rejection' will receive a re-submit link.
Of course, never admitting it was their c0ckup but hey ho, this is certainly Thailand and at least something is being rectified .... hopefully!
Now let's wait and see if I get an edit link.