Since my troubles with Skype and the Dualphone 3088 blog (click here to read), I have some good news.
I persevered with trying to solve the connection, not finding the base unit problems, and eventually the base unit found the internet through the router. I kept the handset and the base unit switched off for a couple of days.
Since then the Dualphone 3088 has performed well, allowing access to free communication to other Skype users around the world, and I consider some of the cheapest international calls available.
Now I would recommend this unit with the latest software download.