My resolve finally gave out and caved in. Four days from order to trans-atlantic delivery though. All hail the Murch!
Do remember that Bob's stuff is 25/28mm which means thay are considerably smaller that Bob Olley's WSD and Killer B offerings, if like me, you're combining the ranges. All those pictured are mounted on two pence pieces, so you can see the difference in size.
However, it's all space age nonsense, so rationlise by saying either the Radon Zombies are just smaller aliens, or Radon energy stunts your growth (or scale-creep). You decide!