Thanks for all your suggestions. Have tried plusgas/Wd40 - failed. Have tried using a torx head - failed, have tried using a centre punch and toffee hammer - failed, will have to try a dremel I guess, but there isn't much of the bolt head showing above the recess in the cover, or drilling it out as last resort. Thanks for the parts diagram, but it doesn't show the bolt unless I'm mistaken. Has anyone got the part number or did you buy from a DIY store etc