Registration figures are not the full story.
Dealer demonstrators get registered but are not translated into sales to members of the public until they get sold on.
If every Triumph dealer has a Bobber demonstrator that's 49 "sales"
The key bit you left out Seeker was "Financial results to the end of June 2017 show Triumph's bike sales also grew, from 56,253 to 63,404,
with 86% sold overseas."
http://www.visordown.com/motorcycle-...es-and-profits
Triumph's UK sales are currently in decline.
In November 2016 they shifted 466 bikes, in November 2017 it was down to 396
Triumph are doing the right thing looking to develop in new markets because the UK bike market is likely to fall on its ****.
You can get the Press Release data (minus the journalistic spin) direct from the MCIA
http://www.mcia.co.uk/sub/Press_Stats