The news is already late and I suspect they'll want to keep Strictly on time, but also not great PR to drop a 70-minute best bits compilation of Children in Need. The EPG now suggests a 50 minute version will air at 6.05pm if the tennis wraps up soon (final tie break beginning now).
Of course, the CiN compilation didn't go out in that slot as scheduled last year either - it was the day after the Paris attacks and so it was moved to BBC2 to make way for an extended news and an episode of Pointless. I can't remember whether it was that occasion or another where the episode of Pointless they showed as a filler was absolutely ancient, about five years old. I knew there was no way they'd have let Strictly start late yesterday, it's surely the one show of the week they absolutely desperately had to start on time. Match of the Day was another consideration, of course.
This reminded me of the Davis Cup weekends around the turn of the century, which always used to overrun spectacularly. I remember being amazed when I first saw this schedule in the Radio Times -
http://genome.ch.bbc.co.uk/schedules/bbcone/london/1999-04-03 - with the tennis going on way into Saturday night (and I seem to recall it running even later and Birds of a Feather not getting on). The Friday session always used to overrun massively as well, and everyone would moan that they'd drop The Simpsons and Robot Wars. I remember one weekend where the coverage was scheduled to finish at six on the Friday, the first match ended at 5.55, and then they announced they were going to show the second match as well and the coverage overran by about three hours. In that period you knew if it was a Davis Cup weekend most of BBC2 would go for a burton.
That said, one of the reasons why it was such a surprise to see so much tennis in primetime is because in the previous decade or so, British tennis had been rubbish and so they never got that far in the Davis Cup.