"Ben Nunn" wrote in message
...
Or will it be one platform be for T5 only, and the other for
both sets of London-bound trains? (which would make more sense
to the traveller, but be logistically more difficult to implement,
and result in a bizarre station where twice as many trains went
in one direction as t'other.)

Based on the plans, it would appear to be the above. Wouldn't be that
difficult to implement; the T123-T5 trains would be completely separate from
the T5-T123-CL & T4-T123-CL trains, the only conflict would be the
convergence between the latter two.

I presume that there will be some flexibility retained to allow trains to
reverse at T123, and possibly run trains from T4 into Platform 1 like they
do now.