Vendor moving goalposts

[GreenSubmarine]

Buying new build from a tiny builder. Originally we were told nov but due to shortages of timber etc we were looking at December.

Now we have a buyer for my property I’ve been told they want a completion by October (unrealistic I know!).

Our deposit relies on a large lump sum (not from our house) which won’t be available to us before December, maybe very early January. Builder is saying no chance they’ll wait (despite ‘understanding’ when we reserved).
At what point can we pull out without incurring too many costs? I’m not bothered about losing survey fees etc. I’m tempted to go along with the October deadline knowing it’s not realistic but if it is then I can say my deposit isn’t available and pull out.
Any advice on how to navigate this would be appreciated!

Ps haven’t bought or sold a house for 20+ years so can’t remember any of this!

Sorry I'm not clear what you're asking from your post? So you would have your buyer sink costs into mortgage arrangement, survey and legal fees knowing you're going to pull out of your sale in October?

Can you sell and rent?

I’m tempted to go along with the October deadline knowing it’s not realistic but if it is then I can say my deposit isn’t available and pull out.

That would be nasty.

If you haven't got access to your deposit money for another 3 months then why have you already sold your house and put an offer in on another one?

That's extremely unfair on your buyers to mislead them. You have to be upfront right now and say that October is impossible and explain why. Let them make an informed decision as to whether they want to hold on, or whether they want to choose something else without incurring any financial losses from surveys etc.

If you weren't going to get the lump sum til December or January, what would you have done if the build was finished on time??

Technically you can pull out with at any point before the day of exchange, but it's a monumentally shitty thing to do to your buyers.

You have to tell your buyer that you can’t complete until January.

If I understand your OP you never could have bought the new build or sold your property until January when you get your deposit.

The only way you can keep this buyer, if they are serious about October, is to sell and then go into rented.

Will the developer accept an exchange in October for a long stop completion? I.e you would sell your property and complete by Oct but only exchange with the developer?

This would give the developer some cash, and certainty.

But put you at massive risk if the balance for completion on the new build didn’t come through.

You can’t string your buyer along by saying October, unless you are prepared to go into rental or stay with someone.

And they will find out anyway when their solicitor talks to yours.

And when they ask the EA for an update on the chain.