Scoble recommended this PUSH Sprint rear guard to me last year (but don't let that put you off).
http://i.ebayimg.com/t/NEW-PUSH-Sprint-Clip-On-Rear-Guard-Carbon-fits-700c-Wheels-Mudguards-/00/s/MjUwWDI1MA==/$T2eC16JHJGwE9n)ySdEoBQGt3V1(5g~~60_1.JPG
It might look a bit dinky and it's not clip-on as the name suggests, but it's easy enough to attach/remove, very light, adjustable and I'm generally really pleased with its performance.
They don't appear to have any at Winstanleys now but I have just found them for sale here: http://www.ebay.co.uk/itm/NEW-PUSH-Sprint-Clip-On-Rear-Guard-Carbon-fits-700c-Wheels-Mudguards-/390449255101?_trksid=p3284.m263&_trkparms=algo%3DSIC%26its%3DI%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D21%26pmod%3D221098399303%26ps%3D54
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Scoble recommended this PUSH Sprint rear guard to me last year (but don't let that put you off).
http://i.ebayimg.com/t/NEW-PUSH-Sprint-Clip-On-Rear-Guard-Carbon-fits-700c-Wheels-Mudguards-/00/s/MjUwWDI1MA==/$T2eC16JHJGwE9n)ySdEoBQGt3V1(5g~~60_1.JPG
It might look a bit dinky and it's not clip-on as the name suggests, but it's easy enough to attach/remove, very light, adjustable and I'm generally really pleased with its performance.
They don't appear to have any at Winstanleys now but I have just found them for sale here: http://www.ebay.co.uk/itm/NEW-PUSH-Sprint-Clip-On-Rear-Guard-Carbon-fits-700c-Wheels-Mudguards-/390449255101?_trksid=p3284.m263&_trkparms=algo%3DSIC%26its%3DI%26itu%3DUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D21%26pmod%3D221098399303%26ps%3D54