I've actually got a rattle free dash at the moment for the first time so I'm tempted to leave it as it is for now. There is one for sale on eBay at the mo' that I'll keep an eye on, but don't wanna pay too much for it!
My local dealer didn't have a price for that part number either, but googling it seems to provide a few results on overseas sites. Maybe it has a different number in the UK for some reason?