@Philjb – not sure if something similar is available in your area but we were are there is a community transport scheme where volunteers use their own cars to as transport for people that don’t drive or cant get out on their own. You pay a per mile “contribution” but at least the car would be suitable for your equipment and the driver understanding / willing to help load it. Works a bit like a taxi service but at a lower cost and more disabled friendly.
Again not sure for your area but there is also a door to door accessible mini bus service that goes to many of the local super markets, shopping centres and attractions – operates to fixed times and days so not as flexible as the above but another option maybe.