Thankfully I have now managed to sort this. The solution is as follows:

Click Office Button

Click Excel Options

Click Add-ins

At the bottom of the ‘View and manage Microsoft Office add-ins’ screen you will see ‘Manage:’ with a drop down menu next to it (showing Excel Add-ins).

From this drop down menu select ‘COM add-ins’ and click the ‘Go’ button next to it.

You will see a list of items, one being Sage Excel Integration. Untick the box next to Sage Excel Integration and click ok.

Then close and then re-open Excel and when you click open documents it should open whatever is shown as the default file location.