Advice on SORN

Having reached nearly 80, my husband & I have decided to forego our winter outings in our motorhome & felt it a good idea to only tax our vehicle for 6 months [May - October. ] Our reminder about car tax has just arrived & we were about to fill in the SORN form when a friend told us it was difficult to get the vehicle taxed again since we couldn't get it MOT'd at the usual time [end of April] because it is illegal to drive without being taxed!

Any advice please.