Actually, I'm starting to suspect that the switch is bad. I connected my XBOX via the same switch and it gave very unreliable results - packets from the internet were just going missing on the return path.

So I could see tracert/ping info leave the switch and return to the switch but not to the correct port.

In case anyone happens to buy one, it's a Corega 5 port switch and cost about £30.

It's in the bin now, replaced with a £30 netgear hub, and all is happy, Rio and XBOX working great.

Paul.