My son was also there yesterday afternoon and enjoyed the D&T "lesson"!
The information about numbers of applicants/interviews/offers isn't easy to come by for most schools (I asked, but the admissions secretary at Habs wouldn't comment on how many offers they made). MTS is very open though - from their website
: "About 300 boys apply. We interview about 220. We offer about 170 places. 50-60 offers are accepted". I imagine it isn't hugely different at St Albans school (who have an intake of "up to 72").
So I've convinced myself that getting through to the 2nd round means they're well on the way to getting an offer
Anyway, nothing more to do now - just have to wait until the letters come out in 4 weeks.