Roof tile edging for gable end

I'm trying to find a supplier for the edging that I've seen used for gable ends on slate roofs. It's like a larger version of what you have for bathroom tiles, and basically nails to the battens, and has a recess that takes the edge of the tiles - makes a really neat job.

Any ideas of what to search for in google?

Cheers.

Steve

Glidevale do one http://www.glidevale.com/downloads/Roof Ventilation.pdf page 30 or google slate dry verge

continuous dry verge here

any roofing supply shed will stock it.....or jewson if you want to pay over the odds