I am putting in Cat 6 and CT100 everywhere in my home as part of a
general re-wire.

I intend to connect my main wideband aerial to a distribution amplifier
in the loft. (I don't have a satellite dish, nor do I plan to get one.)
From the amplifier, I will run co-ax to every room.

Most rooms have just one co-ax outlet. The lounge (the main TV room),
however, has three runs of CT100. Is three enough considering that I
may, at some stage, have cable TV installed in the future?