so the process works as follows (it is for a builder who has multiple sites and plots).
The accountant spreadsheet gets dumped onto an input sheet
User presses a button to clean and then add into a data sheet automatically
if there is a new supplier, it adds this to a company sheet, and colours in the data sheet so the user will know it needs to fill in
when returning to the data sheet, there should be a drop down list only showing what is in the corresponding drop down
it all works well enough. However the user might want to change the set up, and hence why it needs to be sorted. My solution for this was to flag if the company or activity sheet is sorted, then to add back validations for the entire datasheet. It seemed overkill, but we are only talking a few thousand rows so better to be safe.
interesting that you said sorting the columns left to right works for you, it doesnt for me. The project endedup a few thousand lines of code so another dozen wasnt too arduous!