I searched all over for a UK supplier when I had my XT225. I ended up sourcing one from the USA. It was a few years ago and I no longer have the bike, sorry I can't remember the supplier, but google is your friend.
im in the process of having one made for mine,i am going to have it cut out off 4mm alloy plate with folded sides punched out with slots for bungees,it will be fairly simple,and will bolt thru the mudguard,it wont carry much weight but will give support for a bag or light tent,iv bought a big sheet of alloy,and once the machine is programmed it will punch a couple out as easy as one any way,depends whether you want something out of tube or just functional,shout up if you are interested.