Sorry to flog a dead horse here - but I'm now somewhat confused.
As geertvds pointed out, the AIP says you need mode A or C to get into EBOS (this applies to all class C airspace).
The
CAA however references a newer belgian AIC stating that from 1 Jan last year, Mode S is needed in all airspace where SSR was previously required.
So does this mean I need Mode S to get into EBOS, or can I call in advance to get an exemption, or even just call on the radio and let them know?