They can, but, they have to pay "double" the amount of the deposit.
That's correct. Also you can add to that amount your expenses (it happened to me once, we added to the double deposit the costs of transferring funds to Poland and back out of Poland, the costs of currency conversion to PLN and from PLN, the interpreter's bill, the translator's bill, notary costs, lost income from taking time off work to deal with purchase, etc). The seller thought he was going to make a profit by cancelling our purchase and accepting an offer so much higher that he could return double the deposit but he actually came out several thousand zloty down.
what's the point bragging how loaded you are on the internet where you are anonymous?
So why do you boast about your supposed £75,000 a year income?