Just as an update, not my favourite option, but limited choice in the UK unless you have loads of money to spend on postage and customs, so went with the Chinese scooter type fender.
I used this search on eBay:
(Tank, Roketa, Sunl, VIP, Baja, Jonway, TaoTao, Fino, JMstar, Longbo) (fender, mudguard, mud guard)
And managed to get a jonway fender for ÂŁ5. It's still in standard unpainted plastic, but will paint it red to match at some point.
I didn't like the idea of using cable ties, so used stainless steel P clips like these:http://m.ebay.co.uk/itm/322155195525?_mwBanner=1
Worked really well.