I actually can't believe this passed me by until today!
It was revealed on a political podcast (perhaps the Bunker) about a month ago and even they were all shocked (considering they are politics followers).
A month or so before that (so about Feb/March) Andy Street was on the Leading Podcast with Andy Burnham. Street came across as a decent hard-working Mayor to be fair.
And he's even distanced himself from Tory-central from this campaign. Christ, his choice of partner though, couldn't be more Tory.