If there is a track where it's possible to reach 135 in a Focus TDCi, I hope he lets us know, I want to have a go in my Mondeo.
I know nothing about the power output or weight of a diesel Focus, but in a moderately powerful car, with a good run through Camp I'd imagine it was possible to see 120mph at Avon rise at Castle Combe, which would be over 130 on the speedo. It's not a "straight" as such, but it's fairly straight - most things should be able to take Folly without lifting. A bad run through Camp will see you (hopefully) on the infield, or (hopefully not) in the tyres. I've seen both happen.
I had an old Peugeot 405 up to an actual 115mph (GPS indicated rather than speedometer indicated) at Avon rise and that was with a passenger at an "action day" with a vast amount of other cars on the track.
Snetterton is not what it once was, even on the old layout the entry to (what was) the Revett straight was never that fast through Sear. However, Alan Gow won't bring his circus to Combe so we don't have a comparison.
The other thing to remember is that not all venues for track days are race circuits as licensed by the MSA. When we used to run sprints at the Colerne RAF base, we saw well over 160mph (I seem to recall 180mph being achieved on one occasion) through the speed trap at the end of the main runway. Admittedly that was single seaters with the likes of a 3.5L Judd engine (as per normally aspirated F1 cars, in and shortly after the turbo era, albeit with a lot of extra exhaust to meet MSA noise regulations). I might have managed 89mph in a completely standard 39bhp Hillman Imp

.
The track day crowd that also used the venue prior to the last resurfacing used a different layout, but airfield runways generally provide extensive straight lines of tarmac.