MergeClass error when running macro

Hi, I'm at a fairly beginner level with VBA, I have been modifying a script, and as far as I know I have done nothing to the areas that affect any of the .MergeCells = True conditions. But they are all failing with the error 'Run-time error '1004' Unable to set the MergeCells property of the Range class. I have attached the script, could someone please take a look and see if they can spot how this is occurring. If you need the excel document that this relates to let me know and I'll attach it, just thought someone may spot the error in the code initially. Cheers