Aggregate function not working with Filter function

Hello All,

I have been working with a spreadsheet now which I use the Filter formula for, but I would like to improve this by providing a summary of all 'buyers' in this case, not just one at a time, which the Filter formula allows for.

I have tried to use the Aggregate function, but am a little unfamiliar with this and am getting SPILL errors. Ignore the CALC errors - I know why they are appearing and will fix that.

Note - I have had to modify my normal file in order to not exceed the upload limit, which is fine, but the filter may show errors as a result.

Any help would be much appreciated.

Thank you,