Hi Adrian,
Thought I'd reply to the group - also got your email thanks. My Gas meter in the old type with 'analogue' digit numbers the last '0' (.001 M3) has a mirrored centre and using a reflective IR sensor I count the digit as it passes. It seems to work very well as long as the sensor doesn't move - got it stuck with brown packing tape :). the Arduino displays use in watts and rate of use in watts, also outputs the same on the serial port. It's all very alpha at the moment just proof of concept. We have a new electronic electric meter - the type with the flashing led 'once per watt' so just need a photo transistor blue tacked to it. Water, we have a meter with no real way of reading it nothing reflective rotating needles and numbers if you know the type - one thing I have noticed it goes clunk every 10 litres so maybe a piezo sensor to detect the 'click'.......?