Again, my thanks... however I'm not able to accommodate a standard size USB dongle no matter how good or proven it is - the reason being it's a Shuttle with a flap which has to close over the front USB ports.
There are other 2.4Ghz wireless devices on the rear ports and I don't want to cause problems by adding any others to those ports as they can interfere with each other through proximity.
To add to the problem the machine isn't in front of me, so whilst I can test anything on an X86 and X64 pair of computers which I do have here... I've actually yet to load Windows 7 on the machine concerned (it's a Shuttle built on a skt478 Intel 865 board with a 3.4Ghz EE Northwood Pentium IV and 2Gb of RAM)
Here's the actual Chassis, just to illustrate what I mean about the front USB ports...