Are you in a chain? If so I’d ask them nicely and explain the situation and that they arrange the transfer of the extra £1k.
If they aren’t forthcoming then you can choose your level of arsehole behaviour to expedite them sending you the money but there still plenty of time to sort it
Yes exactly.
I just spoke to the estate agent and basically just asked if they could ask the seller if they are happy to arrange privately, at our risk.