I thought it still worth circulating video of the scum-bags who did it as somebody might recognise them. Although they have full-face helmets, so details like the distinctive glasses and arm patch might ring a bell. They left pushing the bike down Baldwin Crescent towards Flodden Road, probably using the alley way near the TA barracks leading to Haslemere Road. I’m guessing they have a lock up or the like locally.
Check out the video and description of the bike here: