Got these suckers out today, not too difficult after all. I used my cheapo 'dremel' thing with a tungsten carbide cutter and ground away a strip of the the metal so the 'o' became a 'c' -thought that might release some of the pressure holding them in, then a combination of thinning the metal around the strip I'd cut and just trying to get screwdrivers and bits of metal in around the edges and hitting them with a hammer and spraying with WD40 until they came loose. VERY satisfying.

Thanks for the help
now just those fecked screws holding the fuel and brake line clips to sort...:rolleyes: