Looks like you can still get the self-install units - plenty of air-con suppliers on line seem to have them. So long as you are OK with the 4m pre-installed piping, there is no requirement for vacuum pumps, gassing, etc. The external unit is pre-purged and the valves in the unit's connector are opened when you lock the quick-connector in place (it's the exact same system that is on mine).
One thing I did find is that you need a fairly large hole to get that connector through the wall (though not as large as someone mentioned in a early reply), so more making good afterwards, and the bend radius of the sheathed pipe&cable bundle is quite large - a pro installation should be neater! I took my piping down through the floor and out through the plinth directly in line with the condenser connector, so mine is fairly neat.