"Now, I've read that the 2008 change over to 406 MHz ELTs is intended to
be world-wide so I'm a bit perturbed by the lack of information or
devices in the UK. If the changeover affects the UK, I'm rather
unwilling to buy a 243 MHz system that will be phased out in a year.

Has anybody heard anything definite about a 406 MHz change-over in the UK?"

The changeover, in effect, will be worldwide. That is because the
satellites that locate the 121.5 beacon and report approximate locations
will shut down. This is the main thrust of the change. The 406 MHz signals
may or may not have gps tied in.

However, the newer beacons will continue to have a 121.5 MHz beacon for
ground searchers to locate the device. It will be lower power, however.
The older beacons will not be declared illegal and still can be used for
radiolocation - however no satellite coverage. In flat terrain, the older
ELTs might still be useful - as long as someone is looking in the general
area. Passing aircraft will still be able to hear your beacon.

Last time I looked, I found no mention of the 243 MHz signal requirement on
the new beacons, so I expect that is going away. I think that was based
upon military requirements and that has gone away.

Colin