Incoming harsh critique, but intended to be constructive:
There are such things as fixed interest accounts - that only pay interest if you make 0/1 withdrawals (potentially with a max withdraw %) before the term is up; and I believe one of the HtB/Lisa ISAs had a 25% penalty (equiv to bonus?) if not used for housing/retirement.
But my thoughts (as usual) wonder to the extreme circumstances - what if the boiler breaks, you lose your job or a sudden expense arises. Or maybe just that cheap car became £50 cheaper. Not having any access to those funds might cause further stress (someone else might buy the car before you). You can’t use a penalty as an incentive instead, as the account doesn’t pay interest - though products on the market would… There is mention of a password locked pot, but you probably know the password.
So, my question is: if you needed to feed your family, what should you do to open a locked pot?
Maybe wait a time-delay? Maybe give a code to a friend? Lower the target so the goal is reached?
Some would say a good financial lesson is learning self-restraint to not take the money, but I understand people do need a bit of help sometimes.