I've only ever used the 8" GGVs. I have a few different ones but at a glance they all look the same. I think my beater disc is GGV1015 that I use for actual adjustments then check final adjustments with a pristine GGV1069.
You won't be charged VAT if the goods are being exported outside the EU. Now includes the UK too. However it does leave you susceptible to taxes and fees upon delivery at the destination address.
I've seen this site a couple of years ago and forgot about it after looking for parts for my 925. Thanks for the reminder!