up to 13 frequencies are coupled together to try and make it work at an affordable cost
Sunny, I think that is Dick's preference, as we know what a huge fan he is of winding back the system so that it once again works at an unaffordable cost.
An extra 12 or 13 controllers handling what 1 controller does now would also bring us more into line with the US (we obviously need to copy from the best), as their system requires 15 times more controllers to run it than ours does.