Delivering the vehicle myself - VT

[aardvaark]

I am currently going through a VT which has been relatively smooth up to now except the recorded delivery notification; it was never delivered so I cannot stress enough, the importance of emailing in addition to any "snail mail". This delay means I will be away from home for Anglia to collect and want to deliver the vehicle to them myself. Why? Because the MOT runs out in a week and the annual service will be due a week later, both of which attract additional charges if expired. My question is, whether I am making any form of legal error by returning the vehicle myself?