Presumably that's "just" Bristol Parkway though? Did they mention anything about Temple Meads?
The interview just repeats the Hendy dates (Dec 2018 to Bristol Parkway/Cardiff/Newbury, later to Bristol TM/Oxford).
But these are "infrastructure complete" dates, not "first electric train".
The "September" date relates to the Reading-Didcot test section later this year.
They are also aiming for Paddington-Maidenhead by the May 2017 timetable change, but that is ahead of the Hendy date (end-June).
It's like a lot of Rail interviews, it reads very positively but doesn't really add much to official statements.
Apparently the HOPS system is doing better at 12-14 piles a night.
There are also remarks that ETCS will be installed to Heathrow/Reading by end-CP5, but it looks like the rest of it has been deferred into CP6.
Resignalling is also critical, with Filton being done this August and the Badminton route next February, then Box, Bristol TM and Oxford.