Good luck, I hope they can supply you with a suitable hire car, contact Motability as they have a different team that deals with these things.
I hope you fare better than I have over the last 3 years, car has been in for repairs 6 times and on every occasion I have had to wait weeks to get a hire car only for them to bring something unsuitable and have to change it 3 or 4 times before I got a vehicle up to scratch.