AUTOMATICALLY Reformulate LOOKUP formulas to INDEX/MATCH (huge file)?

Hi

I have just been sent an extremely large .xlsm workbook (270000 rows approx) by a friend who is not a forum member here but works with excel a lot. He has asked me if I know of any non-manual way to reformulate all LOOKUPS in a workbook to INDEX MATCH formulas (he has been sent the file by a third party (client) and thinks the sheer volume of LOOKUP formulas is massively slowing down the workbook, which is probably true as I have had a look and the file and can't see anything else that would cause it to be slow... and his laptop is by no means a slouch (AMD A10/8GB DDR3 RAM/256Gb SSD/Windows 7/Excel 2010)

Does anyone know of any VBA to reformulate LOOKUP() formulas to =INDEX/MATCH formulas??

unfortunately Manual alteration is not an option here is, as there is a lot of formula variation from row to row (although they are all lookup formulas in some form (so changing the top row and dragging down would not work). The workbook is 270000 rows, each containing 4 numbers and 1 lookup formula

Thanks if anyone can help