For Johnson, he broke the law. For Brand, there have been a few accusations, from 15+ years ago, and no arrest or prosecution, but the main tenor of the coverage seems to be emphasising what a cad he was at that time (today's Gem from the Mail - Billy Connolly had stern words with him for trying to cop off with a wardrobe assistant, and after that he behaved well, put in a great performance, and went on to be a strong supporter of Connolly). His "age-gap" related issue was 31-16 (15 years). For Schofield and Edwards, I believe it related to things they were doing right now at the same time as carrying out A list mainstream media jobs. Still they got far less coverage than Brand is getting. They had much bigger age gaps (30-40+ iirc) if that is what the issue is here.