#DIV/0! Error - Most of the formulas work, except for a small few?!

Hi, reference the attached workbook...

The workbook itself is quite complex but the formula isn't so complicated so I'm not sure why a small number of sites are showing #DIV/0! errors as a result.

If you open the sheet and look at "RC.Total" tab and "RC.Mechanical" tab, Eastleigh, Reading and Jersey show this error. All other sites are as they should be.

I can't figure out what's going wrong with the formula/figures.. Can anybody sus it out? My eyes are going fuzzy looking at it....

Thanks!