Seller offering to break chain for more money. How to make sure they actually complete quickly?
We offered under asking on a property in SW London where the seller has yet to find another house. The seller has asked us to raise our offer, saying he will break the chain and move in to rental if he can't find another place. We're not sure if the seller will actually move into rental, or just take the money and stall during the process while he looks for a house to buy. Is there any way of protecting ourselves from this? Is it normal to set a deadline on the completion date? We don't want to be unrealistic or unfair as we know conveyancing is unpredictable and can take a while, but are also afraid of offering more money for chain-free, only for the seller to take their sweet time anyway.
Also, what is an appropriate additional amount to offer for breaking the chain?
Thanks