Yup - definitely looks like a problem. I am now running just the example web server outlined:
If I run with Serial (ie. just upload the sketch) all is fine. If I then power down the board, remove the usb cable, and power back up, the simple web server does not respond (until I connect back up with a terminal).
Something very very fishy is going on - it's not in my code.
Cheers,
b...