Hi Ian,
I have only seen it when we're installing chairs,nearest to you using them is Stoke I think, John Moore or Peter can give you all the details.
They are really good and have gone through various re-designs along the way.
Somebody should bring one to ART 2016 I'm,happy to host it on our stand perhaps with other technician focused custom products done elsewhere like we used to have,saves everyone re-inventing the wheel e.g. opaque water filter housings which stopped all the algae growth when they were clear perspex.
Cheers,
Chris
www.healthtec.co.uk