If it's a non-fault claim (which it is) you should be able to get a courtesy van with a system installed.
I know Alexander Swan hire out their reach and wash vans to insurance companies who need to provide a replacement van for their clients.
As it's her insurance that's paying, you won't have to pay anything (it will just be billed to her insurance). I think they'll even deliver it free of charge too.
Give them a call, they're a superb company.