Further to my post earlier today, I have in the meantime received a text message from Orange to inform me the increased speed line was set up. I therefore had to dash and open the boxes obtained this morning to start setting things up. Of course it is never as straight forward as it should be. The Livebox 5 needed at least 4 automatic restart, probably to update the internal software / firmware to the latest release.
That took an hour but finally it is working and my iMac is connected to the Livebox via ethernet as well as WIFI if needed.
A first speed check showed 839 Mb/s which is double what I was getting up to now.
It was then time to set up the WIFI repeater which was done in less than a minute thanks to the WPS button.
I could unplug all 3 previous WIFI extenders and ensure all my equipment (mobiles, tablets etc) was set up to connect to the new network.
Next step in a couple of weeks will be the VPN Router via the Raspberry PI set up which I need to pick up in Germany.
Since I only decided last night to upgrade, I am quite pleased that 24 hours later I have a new and functioning set up. Hurray me!!!