Gazza,
I would tend to cool it a bit to be honest! From the different people involved in this transaction, there are different perspectives – the solicitor has one view of things, the purchasers another, and so on. Each probably is right to an extent and depending on their role in the process and interpretation of the facts. I would be inclined to ask the solicitor / estate agent questions to clarify positions first, then challenge the person if that is appropriate once you are fully aware of the ‘facts’ as they have been told them. If you go in all guns blazing, you could end up feeling silly.
("Mortgage approved" could mean different things to different people - for example, I considered myself to be mortgage approved (and told the selling estate agent so) when the bank told me there would be no problem getting a mortgage. I'd no paperwork done though.)
Good luck with the sale.