They're part of the Texatherm cleaning system, as far as i know you can only get them direct from Texatherm, will set you back around 300 quid plus VAT, with a few attachments. Drive plate and 5 bonnet pads come as standard, you'll definitely need a tampico brush and I've also got a couple of the nylon brushes and some black and green floor pads.
Get one, you won't regret it!
www.texatherm.co.uk/One piece of advice, make sure the surface is well lubricated and don't push too hard or allow the drive plate/brush to get wedged in the corner of the stars like I did.
Mine is now making a funny noise when I press hard, I presume I've burred off the teeth of the drive gear or something like that. Need to send it back for repair