School business manager here.
It might be a bit awkward to raise in interview. And how they respond when you do raise it will depend on their pay policy.
But before you confirm acceptance of the job is the right time to raise it. Their pay policy is unlikely to allow for a shift to ups without it being linked to confirmed good performance though.
You might get the opportunity to e plain your situation in the interview. If they ask something like why do you want to come and work for us.
You could say ‘I have loved working at my current school, but having taken time out to have my children, I feel perhaps I got a bit overlooked for extra responsibility ( for instance I missed pay progression x times due to being on maternity leave)
Having now completed x no of years teaching with y evidence I am an effective teacher, I am interested in coming to work At new school as part of a new chAllenge - I am ready to move up onto the upper scale and play more of a whole school role’
When they ask you at the end if you have any questions, ask about potential for leadership development and then ask something about
‘ having been a teacher for x no of years but not even reached the top of the main scale, what sort of fast track could you offer me to help me catch up if I come to work for you?’ But couch it in terms of you being experienced and good potential for taking on more for them. If you have had good recent AppraisAl, chuck that in.
Then, if you get offered the job, when the chair of the panel calls you, say ‘that’s fantastic. I am really excited at the opportunities. You will remember I said at interview I felt I had been held back on the pay scale at x school ... I would like to ask for appointment on m6 when I start with you, and confirmation I would be eligible to apply for threshold after the first year’