Cheers for the replies - would have replied earlier but had to prise my daughter away from barbie.com first
AFAIK the whole bike is stock (I got it 2nd hand, but it all seems fairly standard).
So I need to separate the sides first? Clicking the centre bit of the pin that holds the parts together under the front seat? Then wiggle it and pull the left side off... Where are the grommets that the sides sit in?