A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hi Jomel
This issue appears to have rectified itself! I tried both Internet Explorer and Edge about a week after your message, and again just now, (sorry for delay) and now the 'open in app' feature now appears to be there. I can only assume there was an update which resolved it as I have not changed any settings myself.
Anyway, thanks for your time and help. Hopefully things are ok now!
Philippa