that reg isnt 1961 its 1971 so it must be a typo error on the sellers behalf and if its on the rangie chassis with matching running gear sod evrything else it just might have enough points top scrape through with that reg but only by the skin of its nutsack
a 1961 reg will more often than not be a 3 digit following 3 letters ( eg ABC 123 ) or the other way round as it was 1962 when the fourth year corresponding letter came out
not trying to put anyone down or take the **** im just simply trying to educate and save yer all a little time searching through google /direct gov/dvla and the rest of them