Yes they learned about the need for proper riot gear the hard way back in '80s Brixton where they tried to withstand a shower of half-bricks from nearby demolition sites armed only with a few dustbin lids.
I wouldn't however underestimate the danger posed to ordinary civilians by your average British bobby. Do the Met's patrol vans not all have firearms on board these days? And any comments on the shooting dead by the cops in Brixton last weekend of a man in possession of a cigarette lighter shaped like a pistol? Shades of Diallo - Black while lighting a cigarette?