No Don that is absolutely NOT legal in anyway as Star would confirm as that is mortgage fraud

Sale price £180k
Deposit needed £18k
Mortgage needed £162k

Sollys/buyers negotiated price £170k with a 'gifted deposit' of £10k from vendor.

Seller accepts arrangement as do their sollys.

RICS confirms value at £180k

Buyer deposits £8k
Mortgage lender £162k agrees valuation and is aware of the 'gifted deposit' deal/arrangement.

Seller loses £10k and receives no more than the £170k less fees

The Land Registry will list the value at £180k

So do you see how it is possible to put down a smaller deposit legally on a higher value property rather than just negotiating a straight forward £10k reduction on the price and then subsequently having to still find a deposit of £17k.

Hope that helps