If this failure allowed a train to be signalled onto a wrong direction
track with a train some distance away, held at a signal, then it's
reasonable to also ask whether this same failure would also have allowed
the train to be signalled onto the wrong direction track when there was
a traon 10m away and approaching at 40mph?

i.e. was it just luck that there was no oncoming train in the block or
was the nature of the failure such that it couldn't have happened if the
block was occupied?

I think there's not much we can say until we get to read the RAIB report.

-roy