Thanks for the reply Seth
It seems that pagemash uses mootools, but not jquery and when using Mootools and jQuery together there can be identically named functions and namespaces which conflict with each other.
Statpress SEOlution uses jQuery - the easiest fix for that is to use the original Statpress plugin instead which does display correctly, although I prefer the SEOlution fork.
I have pagemash working well on other sites which use jQuery in other plugins, so I'm not sure how to proceed other than by choosing between which plugin is more useful to the site :o/
What is the best way to disable jQuery from Advanced Events Registration to try what you have suggested?
thanks, Michael