Interseting reading, just one point i'd like to make though having been through this myself.........

I realise that you are speaking for your friend, but its very likely (unless you are their accountant) you will not know all the in's and out's of their finances in the time since they bought this house.

If any payments have been made late etc this can go in the favour of one or the other parties, if any one party has paid more at any time i.e. deposit etc then this can entitle them to a bigger share.

All im saying is, you may not know everything about their situation and thus it makes it very difficult to give exact advice.

the BEST advice i can give is to tell her to get legal advice after having contacted the CAB, they will be able to give her some upfront advice to save her some time when she approaches a solicitor.
As pointed out, using a different solicitor may help the situation, but it can also slow things down, since both parties solicitors will have to keep making communication to each other which not only takes time but inscreases costs.

Good luck, I hope those concerned get the situation resolved quickly and painlessly.