@Ryan thats a shame. Could you not ask your dealer to make the phone call for you? It appears so that this is the only way.
Im surprised they would have separate Motability slots to general public, slots are slots they should be equal and fair as the car technically at retail value costs the same.
Also I called my dealer today who wasnt there but had a conversation with another person and they said some orders were being delayed and this was mainly orders with lumbar support. I havent ordered this. I went to have a look at the online configurator too and it does say temporary restrictions so im not sure how much of an influence this will have on peoples order with the lumbar support.