DFC
I agree with you (and para b, obviously) that you have to intercept the inbound track before reaching the facility. The issue is that, in order to descend according to the charted profile, you have to intercept the inbound track not just before reaching the facility but before the point at which you need to leave the altitude of the inbound turn.
In the case of Calais, you need to leave the altitude of the inbound turn (2000 ft) at 6.1d, some 2.1d before the MK, so you have to be established by then. I don't believe that can be done reliably with a sensible intercept angle, given that the outbound is just 1'30", i.e. potentially less than 3.5 miles.
Trying the scenario on a sim proves only that it's possible to manhandle an aeroplane in such a way that it sometimes works, presumably with some extreme intercept angle. I thought IAPs were designed so that they always work.