thats how it was told to me mate but its not exactly clear.

I would say send them off the original SORN with a covering letter saying you believed it was still covered when ownership was transfered ( avoid pic of shell on trailer as they may then swipe your V5 off you) and you never know your luck.

watch out though as while they decide, the fine might automatically go up, might be worth just biting the bullet but I know how you feel