Nigel they are made by Raleigh and I got them off ebay here. These are for 20" wheeled Moutlons. Mudguards for 17" wheeled Moultons are only available directly from AM I think.
http://www.ebay.co.uk/itm/NEW-Raleig...item2eb122732f
However although I have not tried them, I think these look better as the stays can be adjusted easier than the ones I have above which require cutting to the correct length which is a bit hit and miss. My stays are still too long. The Raleigh ones do have nice mud flaps on the ends though.
http://www.ebay.co.uk/itm/NEW-SKS-20...item2eb581347e
Or here cheaper and with free delivery
http://www.chainreactioncycles.com/M...?ModelID=25794
The alternative is to get more expensive ones from AM/Pashley though I hear mixed reports about them and breakages.
PS NOTE you will have to modify the front stays to take account of the suspension fork leading links (put a kink in them) so that they do not fowl them as they travel up and down. The AM/Pashley ones of course are supplied with correct shaped stays to overcome this.
Regards
Jerry