Cannondale CAAD 8 Ultralight Touring Bike.

£55 quid a piece. Not cheap. They sound good but I would want to see how well they last in London before splashing the cash.

Better than the Challenge that's for sure, I rode the 32mm to Morocco and had 4 puncture (most are within 50km of Casablanca).

You may like to hold out for the HED Ardennes+ .. supposed to be a 25mm wide rim 21mm inner weighing in at 435g when it's released

Saw that too, the 21mm internal is surprisingly wider than the Mavic A719 (19mm), the best tyres I've ever ridden on is the 32mm Grand Bois Cypres on the Mavic A319 rims.

Will wait for that one, cheer.