Thanks Tony, will give it a go on Monday.
I think a potential problem will be that I instead of referencing direct columns I need to lookup the column reference - so I will need to use something like INDEX(ARRAY, 0, MATCH()) to replace "B$1:B$6" - unsure how to use this in the context of a RANGE:CELL type formula. Much easier in VBA but unfortunately not available in this case.
So in this case if you can imagine column names in cells E1:E3 and the same column headers replacing B,C&D