Autosum not working on a selection of values since upgrading to Windows 10?

Question

I have an issue with totalling up a column of values since upgrading to windows 10. 

I have exported a spreadsheet and want to highlight a chunk of figures and get a quick total in the status bar. Usually doing this highlights the sum without physically creating the formula on the spreadsheet, it shows in the status bar at the bottom however nothing is happening since i've upgraded to Windows 10? 

If I manually add the sum formula this also does not work now? 

I have checked that formula setting is set to calculate automatically. 

I have even cut and paste the values into notepad to remove any formatting and pasted back in as values and nothing. 

The only think I have noticed is that since upgrading to Windows 10 my excel has now defaulted to have an american currency? I have tried going to 'More number formats' and set this to English £ however every time I open a document it reverts back??? 

The only way I have found to get the sum formula to work currently is to over ride the figures in the spreadsheet and manually type them in myself and this then adds up. However I can't manually over ride rows and rows of exported values??? 

Please help as I need to autosum lots of values and can't work out why this function has stopped working??