Ok gang,
I think I've resolved the issue concerning 'Incoming connections from OpenDNS servers ?'
I emailed OpenDNS and received a very courteous reply from one of their support people, who told me that their servers only ever send out responses to valid DNS enquiries. I just could not account for why this had suddenly started happening, although in the back of my mind I kind of remembered something about a tick box saying something along the lines of 'Use openDNS', but for the life of me, I just could not remember where that was from. A little 'googling' pointed to an application by Apple called Bonjour, which apparently gets installed by stealth when you install any Apple software. I went through the uninstall process for that application, sometime during yesterday, and haven't received any further repeats of the openDNS connections.
Just thought you all (or some of you) might like to know.
TTFN
toulouse