if you intend to move to the nearside and a car is there and you no longer have space to move and you want to take first exit at the fast approaching roundabout then you have not planned correctly, so you ask yourself what do i do, well you either hold back and move behind the car, or make sure you enter the roundabout first and get over to the left asap. If you dont know what you are doing then you will put yourself in these tricky situations. Advanced training prevents this because you are planning so far in advance you wont be waiting to move over til oops shit crap theres a car there moment, you have just described a perfect example of how advanced training could make you better erm well safer.
the use of indicators is explained perfectly by Shrek.
What i said previously was when actually training to take my bike test the instructor said you indicate out to the outside line but not when coming back in, this is nothing to do with advanced training. At the end of the day if you need to put you indicator to let other road users know your intentions then use it, if there are no other road users in sight then why would you signal, there is no one to signal to.
also the highway code i believe states that if your have no indicators arm signals can be used, just like a pedal cyclist for example, when they change lanes they point with there arms, its something road users do everyday, i normally point when in heavy slow moving traffic, this is a clear and simple way of letting someone know you intend to move in front of them from being in the outside lane or maybe filtering and need to move over, for a turn off.
Also the planning advanced training teaches means you could pretty much travel accross a busy town one side to the other without using the brakes and only using them when coming to a complete stop and even then this is minimal because planning on the approach to lights should be minimising this.
you wont understand this technique until you are taught or made to try it.
and trust me it makes you a lot quicker and a lot safer, because its all down to planning.