yes this does need welding up, the mot rules as far as i can remember on vehicles with a chassis is there is to be no corrosion damage within 30 cm of a body mounting or seat mounting or seatbelt mounting. on your vehicle it is right next to the front body mountings, so needs to be sorted for its next mot. i dont think you are in any immediate danger of the body falling off, but please get it sorted soon for your own safety. steve