Too Many Different Cell Formats Error

I have a relatively complicated spreadsheet 'process' which involves a number of different people filling in Excel based progress reports, in similar formats (created from the same template), and then invoking a common "publish" VBA macro which opens a common "master" workbook and copies their sheet into the master one ( deleting any previous one of the same name). The master sheet thus contains around 30 similar sheets published from different people, plus a couple of summary sheets. Note I also then copy cells in order to get around the 255 character limit on worksheet copy

All works fine except this week it decided to raise the "Too Many Cell Formats" error when trying to open the master workbook. I didnt know about this error, but apparently there's a limit of around 4000 cell formats per workbook. Given that the individual sheets are similar, I presumed that they wouldnt all have their own cell formats. I dont know how to check the number of different cell formats (it's not the same as checking the number of styles) or how to condense them to avoid any limit.

Looking at the actual styles defined in the master workbook, it seems that styles are duplicated when sheets are copied - I have multiple "normal" and "hyperlink" styles. I dont know why, or how to avoid this.

So - any ideas on how to avoid multiple cell formats (or even styles) when doing a worksheet copy into a different workbook? It needs to be an automated solution (i.e. macro) - I'm not able to go in and perform manual operations every time someone publishes (i.e. copies in) a new worksheet