Put the date you acquired it as yesterday from persons unknown. Or make something up.
That way you won’t get any fines in the interim.
As long as there’s not a stolen marker on it they won’t care.
I forgot to register a truck here 5 years ago. Sold it last month to a boy I know. He applied for logbook as ‘not present’. He got a new V5. I assume sorn fines and whatnot went to my old address. Not that I care enough to find out.