I was in the Triumph factory 2 in Hinckley on Monday (6th June) It was very interesting. The guide said a few things that were interesting, I will try and get it all right.
Triumph are expanding rapidly, Factory 1 is basically a big warehouse and no bikes are made there. All the new models, R+D, concept/design is done in factory 2. The new models are all made in factory 2, When models are older the production is moved to Thailand and that includes all bonnevilles. This is simply to make room on the production line for the new stuff. He said the pass rate for bikes off the production line was highest at factory 2 at about 98% but it was lower at the other factories ( He said what it was but I can't remember)
What we did see on the engine prodution line was tiger800, thunderbird storm and rocket engines being made. The complete bikes were on an other line and it was mostly the new tigers with a few thunderbirds and one or two rockets.The guy said they were selling loads of the new tigers and they were being made to order, there is a waiting list to get one.
So if you want a Triumph that is made in England buy an early example of the bike or buy a new model.