CD goes in with radio on.
CD error! screen
Turned radio off, the on.
Flasher loader starts, and will keep rebooting or turn off and never complete. Was stuck here for a couple of days until I read the manufacturers sheet
On start (before flasher screen is displayed) press 3 4 5 6 >> (sheet actually says to do this while it says "do not turn off radio" on flasher screen so YMMV)
The radio lights all flash
The programming actually starts
Then the Alfa logo stays on permanently (left for ~60 mins as was driving)
Was still stuck on with the engine off (i.e., in danger of running down the battery)
Pulled neg lead on battery to disconnect
Replaced after 5 mins
Radio now started with new firmware, and Dension 300 GW device suddenly started working (result!)
But I really thought I had killed it... and nearly ordered a Pioneer replacement. Now I don't have an excuse

Or I may anyway as the Connect Nav+ is an expensive poc
Had to reset door window anti pinch as I had removed battery with door open (not good!) [using drivers window down 10s, passenger down 10s, passenger up 10s, drivers up 10s. then windows worked normally]