Contract exchanged and additional job offer

Jimmy-2-Shoes

Well, about to exchange contracts (literally today or tomorrow) but completion of property not due until end of October. Partner has been in same profession for years and has been offered additional job teaching about the profession. This will involve working in usual job one week and alternate weeks at a university. Therefore she has requested that her hours at the usual job accommodate this and her employers have agreed to this from November for a maximum of one year. She retains her normal job and can revert to full hours whenever she requests. The University job pays greater pro-rata so net salary will increase and there is still the security of full hours at any time with existing job. No formal offer has yet been made of the job and while she has made informal inquiries about reducing her hours from November, nothing has been signed.

My query is is it necessary to inform the lender? Obviously I have a big fear of anything going wrong- ordered a sofa and everything! Nothing is in concrete yet regarding the additional job but fear it could result in mortgage offer being withdrawn if, for whatever reason, completion does not happen at the end of October and they somehow find out that hours at normal job have been reduced.

Also fear that if we tell them now, it might prolong exchange of contracts (and there is a deadline for this week) and actually nothing would be able to back up the salary of the new job or that it had been offered.

My gut is telling me to just sit tight- she still has her old job- but is there anything that could go wrong with this either way?