and thanks Just Answer.
My name is ***** ***** am happy to assist you with your enquiry.
Sadly, in English Conveyancing law, either party can withdraw from a Sale without any liability to the other party, at any time before Contracts are exchanged. Therefore, you have no grounds whatsoever to make any financial claim against your Buyer's Buyer delay, however frustrating it may be.
The only thing you can do is to issue an ultimatum to your Buyers saying that unless
they exchange Contracts by such a date and complete by such a date, that you will withdraw from the Sale. Although this may only be a veiled threat, it is the only thing you can do to force the issue. This will hopefully make your Buyers issue a similar ultimatum to their Buyer. You should get your Solicitor to email/fax the other side confirming the above and it would be best if you notified your Estate Agents also, as they will be able to speak to your Buyer directly and hopefully your Buyers Estate Agents in the hope that they speak to their Buyers.
I am sorry I can't give you a magical answer, but hopefully if you at least threaten this ultimatum, normally I find the other parties get to the finishing post in time.