Failing the canti mount, the Tektro R559 is the best one if you still have brake mount on the frame, they're pretty powerful with different pads, and clear a 45mm mudguard with no problem whatsoever (plus 38mm).
An example with 58mm mudguard and 42mm Grand Bois Hetres build on a frame designed for 700c;
Great info scolbes. The 559 is what I was originally looking at, but amey's and other's low opinions of them made me doubt. I guess probably worth a crack for £40.
Failing the canti mount, the Tektro R559 is the best one if you still have brake mount on the frame, they're pretty powerful with different pads, and clear a 45mm mudguard with no problem whatsoever (plus 38mm).
An example with 58mm mudguard and 42mm Grand Bois Hetres build on a frame designed for 700c;