Here's number 2 & it's a wee cracker;
How to empty any radiator without all that messy draining!!!
Get a 1/2" radiator brass air plug, solder a schuders(?) tyre air valve into it.
Turn off both the LS & TRV, remove any of the two top plugs from the radiator & connect your soldered plug(above), open your LS radiator valve, connect a foot pump to your air valve, pump all the water out the radiator(this will go into the F&E tank or out through the PRV if the system water pressure goes above 3Bar). You'll hear the air gurgle through the LS valve when the rad is empty, then turn off the LS valve before disconnecting the radiator. You should be left with little or no water in the radiator, but always have a few old towels & plastic dish to hand - you don't want to damage the white deep s**g pile!!!..........
PS. For the hard of thinking, don't forget to cap the TRV!!!
Or do what I do, and use the (overpriced) Kamco inhibitor introduction pump