Delayed completion - mortgage offer expires

Zinny12

Buying from someone downsizing to a new build - the developer wants them to exchange in the next few weeks for a completion date of mid Nov. We agreed to let them stay until completion - we would have lost out to higher bids otherwise. Which means we need to exchange with the vendor in the next few weeks and have a long completion date (our house is sold and exchange/completion ready to take place - with us able to move in with family until Nov). We changed our mortgage (same provider who we agreed the original mortgage with in April) a few weeks ago with all the same underwriter checks and up to date payslips - with the expectation it would be 6 months offer and cover Nov - but this new offer does not extend to the planned completion date. Hadnt realised the offer is based on credit checks and property valuation done at first contact with the provider and so expires in October. Appreciate risks of a long completion date anyway - we have met the vendor and reassured etc as much as anyone can be - but any suggestions on how to overcome offer problem? I see options as:

try and persuade provider to give an extra month on offer? (No so far)

get another offer from another provider - probably too late

ask vendor to agree to complete a month early at least on paper for now

anything else?

Thanks for any advice

rudesupermarkets

Have you asked the lender what extension options are available?  the lender I'm using has a bog standard 28 days, but also has an option (Not publicised/ advertised) to extend for 90 days if contracts have been exchanged. The only caveat was the option may not be available, or terms differ, when the time comes (we're a few months away from offer expiry).

Zinny12

Just to say we had outstanding service from Natwest (as a new provider) who spoke to us, credit checks, valued the property and gave us a mortgage offer in 4 days which extends beyond the delayed completion date. Might seem obvious to the well informed but our solicitor did not flag the issue with delayed completion of our original mortgage offer expiring by completion date being an issue at exchange