Peter, it is relevant because £150k was the figure we received and the percentage was 25. It was done as a deal whereby that percentage would be carried forward to any future sale, but only beyond the £600k mark (which is the starting point, as they have already given us 25% of that amount.)
I don't know how to put it any other way.
I do hope you see it now. I know it is a rather odd way of agreeing a sale, but that is how it was.