DVLA should already know as those codes are on your driving licence and they issued the licence.
What the codes do is tell the police in the event of being pulled over that you require those adaption and of course if there not there your ticketed, I assume, for driving without the acquired adaptions.
I left Motability for 6 months in 2018 and just told my private insurance company my license number and that tells them I need adaption. My car adaption were fitted by an approved Motability installer as the car was an ex-Motability car but not sure where you stand if adaptions are self made or fitted by ones self from second-hand equipment as Motability and RSA will not let you use some adaption that have previously been fitted to another car as is the case with Lodgesons remote controls.