If those Microsoft jobs are from the Thames Valley that would be highly significant!
They're not, they're surely local. In a market so competitive for talent, they'd lose too many key staff by making them shift out of the SE to Manchester. Linkedin would be on fire in that space and it's not. It's only a 100 staff office, that's pretty small, so nothing major, certainly unlikely to be filling the front end on a regular basis going West. Virgin Trains on the other hand.... Depends what division, if it's Azure, there could be no reason to travel to US at all.