Yes I figured it all out (I'd already encountered the issue with sheet/cell protection) eventually.
I've uploaded the "almost completed" sheet. You can see that if the state of the chkbox (@B102) is toggled, then the protected state of the input cell for Annual lease costs is toggled too.
When the sheet is being used all the numeric entry fields which are black in font colour will be protected (they are calculated values). The red cells are required entry by the user.....and by default chkbox B102 will be disabled. Hence the user (me or my wife) enables this when they are analysing a high street retailer - i.e. they have hidden lease costs which are capitalised and subtracted from operational pro, and a bunch more parameters are then produced for valuation.
thanks again for all your help
