I haven't a clue at all how many have been done, and I'm a bit gutted I missed out on a trip today. I saw it Seaburn bound on Thompson Road getting close to 5pm, so if you saw 564 at Sunderland at 16:05 then this should have been the same bus I saw. But it definitely had a flip-dot matrix destination with the 99 number, so who knows what happened! Maybe I could have been seeing things and convinced myself I'd seen the 592 instead, but I'd only just passed a Doxford Clipper MPD on the 592 minutes earlier!
I think I read somewhere that one of the Street Shuttles had the new moquette. I thought a canny few MPD's across the fleet had been treated, including some of the East Durham fleet; but it looks like I'm mistaken - they're rather few and far between!