Insurance query - replacement hire bike

As some of you know my other half got knocked off his bike the other day. Thankfully he's fine, but the bike is unrideable and likely to be written off.

In theory it's a fairly straightforward situation - the other party drove into the back of him in a traffic queue and has admitted liability (at least in front of witnesses - not sure what they'll put on their insurance form though!).

We have fully comp cover and Etienne wants a replacement bike while the claim is processed. However Carole Nash is refusing to provide a replacement on the grounds that he also owns a car, even though the car is currently having some work done on it and won't be ready until mid next week. In the meantime Etienne can't get to work as there's no public transport option (retail park off the M3).

Carole Nash are citing something about the regulator not allowing for a replacement bike where another vehicle is available (I'm assuming an attempt to keep insurance costs across the industry down?), and have also said that because the car has been used since the bike accident we just have to get it sorted out and use that instead. What they also aren't getting is that having access to a car isn't the same as having a bike to ride for the summer.

I guess the alternative is to try and fix this up via the solicitors dealing with the case and reclaim from the third party, although the insurer seems to think we'll only be allowed c. £10/day even if we are able to sort it out (which might just about afford a C90!!)

Has anyone else had any experience of this, or have insider knowledge which might help?

cheers