Hi Conor, glad to see you're finally getting into the cold, dark waters off the British Isles. Hope you find it as enjoyable as the tropical diving has been to date.
Azatty, either your link doesn't work or my browser is broken.
As for Usil's diving method, it's not that unusual: here in Ireland we dive 7mm semi-dry suits, also without BCDs. Some of my buddies have gone the whole hog and have done away with those pesky air tanks: instead they use very long snorkels with a buoy on top to keep the flexible corrugated tube afloat, but I think that's just taking things too far.
Back to semi-dry diving without BCDs: we use brass carabiners to clip sandbags on to a webbing belt around our waists to compensate for the air trapped in the neoprene. At the end of a dive we simply unclip them and leave them on the bottom when we want to ascend (it's okay - they're hessian bags containing unwashed sand, so they're totally environmentally friendly). At this point, the positive buoyancy of the suit takes over and we float effortlessly to the surface.
It's a great rapid-ascent procedure that makes use of elementary physics and is foolproof, though, of course, (here's the disclaimer) I don't advocate it as a system for anybody not properly trained in it. The rush of adrenaline as you rocket to the surface and then get airborne has to be experienced to be believed. We have competitions to see who can leap furthest out of the water using this procedure to ascend from 30 metres.
Similarly with diving a dry suit: as Leadweight points out, all it takes to ascend to the surface in the event of a flooded suit is to jettison your weight belt and surrender control of your ascent. So it's not a big deal, right?
Nessie, I've seen quite a few recreational divers who dive with unserviced or faulty equipment, zero dive planning, no emergency plan, and untrained buddies. But I often wonder if they're for real.
ut:
