Thanks Andrew. I went ahead and installed Brigantia and it's better - the
display is improved for one thing, I haven't explored everything yet.
I'm really impressed by how complete and sophisticated the system feels. I
was expecting to have to take a fairly big step backwards.
The installer did seem to hang on both occasions - 4.0 from the card and 5.5
from the USB stick I just made - but tapping ESC and a few random keys a few
times, seemed to unstick it... oh and in the latter case removing the network
connection... luckily I'd seen another post on the forum about installing
without the network.
All good now, running updates.