Hi, yes I did read and understand Yellow Saddle's much appreciated comments, and was only drawn to the Campag's because they were designed specifically as CX wheels according to the blurb.They are on offer for £100, but should be around £160. Not that cheap really! The Rear has 24 spokes not 20 as per my previous e-mail, but I agree it is still not many is it. Thanks again for your advice.H+ Plus Son don't do rims for 16 spokes. the lowest you can get is 20 h.
It's disturbing that a builder would build a rear wheel with 20 off the shelf spokes, they are just not strong enough.
Maybe you didn't read or understood @Yellow Saddle post. If I were you I would put the £100 towards something more durable or if budget is an issue then you might have to go second hand or something heavier but also cheaper.