Handing in notice before exchange and completion

Spring89

Hi everyone,

My partner and I are first time buyers and got our mortgage approved 2 weeks ago. I am a teacher and had initially planned to hand in my notice at work at the end of May (notice deadline to be able to leave this academic year at the end of July) and start a new job in August in family support which pays slightly less. If i miss the notice deadline i can next leave my job in December which i really don't want to have to do also as it's very long commute from the new house we are purchasing. I had thought exchange and completion would've happened by then but now I realise it may happen after my deadline. In which case I'm nervous to hand in my notice (to leave in July) at the end of May if mortgage isnt complete - how likely is it for lenders call your employer just before exchange/ completion?
I'd still be getting paid so can provide pay slips- just aware that youre meant to notify your lender if you hand in your notice.

Thanks