Hi Radical,

Thanks for the information. Unfortunately I still have not been able to pin point the cause of the issue.

The 1440p laptop is actually my better laptop with an i7 8550u 16GB ram vs my work laptop with an i5 6200u 8GB ram (which has no issues with the file).

I think its a driver optimisation issue with either the resolution or trackpad(?). It appears to only happen when I use the trackpad (two finger swipe) to scroll - even if i leave the file open for 5 minutes to 'load', the use of the trackpad makes excel non-responsive. My work around is to scroll down the sheet from top to bottom slowly by holding and dragging the side tab (I do this straight away when opening the file) - after doing this I can use the trackpad to scroll with no issues.

Its a strange one...and all my drivers are up to date