Vehicle tax

If you are the insured on an existing contract no - you will (should) have already declared your disabilities to DVLA if notifiable, and your insurance company always (and probably be on a "medical" licence.)

In theory it should not for others (equalities act) but that has not been my experience. The fact that in most cases DVLA remove B1 C1 and HGV/psv classes from your licence allows the actuaries to argue that DVLA therefore assess you as a greater risk so they can as well. For non drivers the argument is the higher risk of sustaining damage as a passenger in an accident / difficulty of evacuating vehicle in a fire etc.

Insurance only asks if you have any DVLA declarable medical conditions - I have conditions which are not required to be notified to DVLA and hence my insurance doesn't ask or need to know about them. Ditto I don't have a medically limited driving licence.