Your right daz there not vibram sole,, I always thought they were , just looked on muck boots own site,,, think they have just copied the vibram design ,,
The ones I have now, that I thought were vibram but arnt,,lol, are better than those Avons , those Avons realy were shite,, just trying to sand upright on wet grass, was like watching a Charlie Chaplin film...always. On your arse .
Looking on there own site,, they seem to have a better selection then we get here,,, they do full rubber boots, here's the link
http://www.muckbootcompany.com/men/outdoor-sporting/Pages/default.aspx