As promised, am posting back with results...
In short, it works and was dead easy to install and use. Coupla drivers need to be installed on the laptop first (these are supplied with instructions), and then the scantools.net software.
Plugged the interface into the car, started the engine, started scantools, waited a short while while comms were established and then clicked 'Read Codes'. Within a few seconds, the fault code (which happened to be P1135 - see
here ) was returned. Just needed to look up the meaning on www.troublecodes.net (an example - there are others too) as the code is a manufacturer specific code. I believe that scantools will interpret generic codes for you instead.
Note that some of the other options in scantools didn't seem to be functional, so you may need to use another application if you want to use these - I think there are a quite a few available - indeed there are some others supplied.
Note that the software and drivers are supplied on 3" CDs which may not be suitable for slot loading CD drives.
So, should any other LOC members need codes read, and they can get to me in Billericay, Essex, I'd be happy to do the honours - could save you a few quid. Just let me know.
Going to try it out on Mrs sh's Smart next!!