Have not resoved but understand better and able to replicate.
Report/results.rslt contains only tab seperated data. There are no headings in the file.
On the actual Report Explorer you can drag the column width of the far right hand side columns so they actually dissappear. The actual "data" for these columns remains in Report/results.rslt. But uness you use some other program like I used notepad its not visible. If you repeat process you can delete futher columns. I'm actually missing the last 3 standard columns.
So its the "Heading" or "structure" thats actually being deleted, as the "data" is still OK.
Have tried a buch of things to "undo" but its beyond my pay grade.
As my laptop is without seperate numerical keyboard I needed to use the Windows OnScreen KeyBoard in the end to obtain the NumLock "plus" sign (doesnt work with only CTRL + ALT + "+" or CTRL + ALT + SHIFT + "+")