Apologies, I guess you've partly answered it for me as i know that pivot wont work from my original data.

I've now attached a new version of my data where I've used some formulas to get me part way there. It now has the data sorted into the amount of minutes in each interval already.

So now I need to go from the source data on the 'Data' sheet of attached workbook, to create a pivot table to look like what I have in the 'Result' sheet.

Thanks again for continued help !SampleData2.xlsx