I agree Risso - it is shambolic that we don't kno wwhen he'll start. But I've been thinking (and maybe this has already been said further back) but this is not a "standard" appointment. If Hoillier was coming from another club they'd want him out immediately so he has little time to tap up players and coaching staff, and so they can get the next guy in ASAP.
But in this case he's not coming from a club and so maybe the FFF don't need to shove him out so quick, maybe he's contractually obligated to work some kind of notice, and they are enforcing that on him. Maybe this isn't all Hoillier's choice and breaking his contract with immediate effect could leave him open to compensation claims? By him dancing to their tune he can ger out in a matter of days/ weeks rather than the 3 months that he obviously has in the contract - didn't he say that himself?
Having said all that - this could all be him pandering to their requests to keep in with the FFF. Randy could propably help with a comensation claim if needed