After much shopping around and checking I bought a VION A100LD MIC CERT. It has a large scale and is much more sensitive than most in the sub £100 price range. So far I've been very pleased with it, it's easy to read slight changes in pressure and appears to be well made, I also bought the matching clock which keeps good time. Another good feature is it can be removed from it's mounting easily. (hopefully not by the low-lifes)