Nothing in the error logs, and as it's currently running on localhost anyway, I'm outputting all errors and warnings to the screen.
Good spot on the toolbar, the joys of copy and paste - I don't actually need that one!
There's something very odd going on, I've also just had a fiddle around to see if I could still print_r the $vbulletin object before I run vb_Template::create but it now does nothing, and even commenting out the template commands at the end of the script has no effect - the template is still displayed!! Don't think it's a caching issue as I've cleared the cache a number of times...