I was always taught to base my lane choice (on simple roundabouts) on the sign which is on the approach. Even if the actual layout of the roundabout is slightly different. If it is up to (and including) 12 o'clock, then left lane is "usually" the correct one. If it is after 12 o'clock, the right lane is "usually" the correct one.
However, there are plenty of times when less-obvious things occur. There are many junctions out there where the left lane is for going left only and the right lane is for straight and right... Even though the right lane actually points you into the central reservation of the road in front of you. Without any road signs or markings, the left lane would make more sense for going straight on, but that's not how they made it.
In short, every roundabout and every junction will have its own way of handling it. Rote learning when it comes to driving is not wise in these cases. You need to use a case-by-case approach on all of them.
Use the road signs and the markings on the roads. When approaching a complex roundabout, look at the roadsign to see which road you want to take (either the road number or the town that road will take you to). Typically the roadsigns will say something like M6(S) or M'Chstr (what ever the abbreviation of Manchester is) or something. If the road ahead is the A537, you need to be aware of that when you look at the road sign - The roundabout may not make it clear that the lane you're in is the "straight on" one and it may only refer to the road number.
Generally the "leftish" lanes are for going left, the "centralish" lanes are for going straight over and the "rightish" lanes are for going right, but they will cross over if there are several lanes going in and several lanes going out of a roundabout. If you're going right around a complex roundabout, you may have to start moving over into the left lanes as you go around. If you get in the correct lane and follow the directions, it should automatically bring you towards the outside of the roundabout as you approach your exit.
In summary: Use the road sign to find which road to follow. Look to see if it has any directions on lane position. If it does not, use the road markings. If there are no road markings (worn out, painted over, or a simple roundabout) then use the clock method to find an appropriate lane. Just treat each scenario independent of the last because they will likely all be different. Avoid memorising techniques as inevitably there will be a junction or roundabout out there which does not fit the trend. Awareness is fine, but treat them all separately.