Deleted Columns Importing into PBI & Making Workbook too large

Hi SergeiBaklan thanks for the response.

I am not sure if I have the Pro version or not, its a business account - I assumed that was a different level unto its own.

I gave the Clear All Formatting option on the Editing section of the Home ribbon a try, by selecting the Columns & Rows in question first. It seemed to help with columns, but not rows and heres why;

• I have 2 tabs on my workbook. One tab has around 300 rows of data and the other has around 900.
• When i scroll down half way through each, the vertical scroll bar is radically different on the two of them. On the 900, its not moved at all, where as the 300 is half way to the bottom.
• Likewise, when I navigate to the bottom of the entered data for each tab, the 300 tabs vertical scroll bar is pretty much at the bottom. Sure I can continue scrolling down and the vertical scroll bar shrinks to accommodate. But when I go back to the top, the scroll bar gets bigger again, as though we never scrolled down. 
• However, on the 900 row tab, when looking at the final few rows of data, the vertical scroll bar is still pretty much at the top of the screen.

This has me thinking that, for some reason, Excel is still looking for all 100,000 rows on that tab, instead of simply the 900 or so that I am using. Is this is a known issue, or something I can work around?