Buy property as a limited company, manipulate the seller and avoid being held to any contract ?!

When someone bought my son’s house in the south of England , as it was going to be redeveloped (knocked down and 4 news houses built) the buyer asked if they could buy it in the name of a new LTD company, which the person would be the director of (it’s one of many LTD companies they’ve set up to buy land/properties from people before).

With time moving on, the buyer agreed to exchange contracts early to provide reassurances that they were fully commited, but they would only pay a 2.5% deposit rather than 10%, and they would need at least 6 weeks to pull all the funds together before the agreed completion date, which they felt confident they could do.

The completion date was last week, and they have not paid….

Tired of waiting my son’s told them he’s going to rescind the contract, but they have come back to say they need more time to get the money and he should give them that otherwise they can simply wind up the LTD company and he’ll get nothing more. Their Solictor has proven to my son’s solicitor that they have most of the funds sitting with their Solictor, but just say that their solicitor will simply send the money back if more time is not given or a new arrangement cannot be reached etc..

Is it really that simple for someone using a LTD to manipulate things like this and can avoid paying any of the money owed if my son rescinds; in this case it would be the remaining 7.5% - to make it up to 10% which the contract they signed stipulates?