No. You cannot use any application which sits outwith the exam platform. This is a closed book assessment and attempting to access an external application will force you out of the assessment platform.
If you need to take notes during the assessment you can use the notepad function on the platform or your blank paper.
You can only use the Excel spreadsheet embedded within the assessment platform. If you elect to use additional tabs within this spreadsheet to carry out work on other questions that is permitted, but you cannot, under any circumstances, open Excel software from any other source. Any workings carried out on separate tabs will not be marked.