The question was that ATC control was retained throughout the exercise
How can ATC control you outside controlled airspace? If you are receiving a a service from an approach unit then there is an assumption that you will follow their instructions unless you make it clear that you will not, but you are not being controlled. You are simply receiving a service. In fact my experience of Belfast (admittedly fairly limited) is that they generally tell you that you that you are on a flight information service the second you leave their zone.
you might look a bit daft asking if that means you cleared to enter the zone
You might also look a bit daft, when the controller complains that you entered controlled airspace without a clearance, if he was simply telling you where he wanted you to go once you were cleared in, but he hadn't actually cleared you in.
For example on the odd occasion returning to Dublin I would get a call like "XXX report Dunshaughlin not above 1000. We're quite busy at the moment so you can expect Broadmeadows hold for runway 29. But Dunshaughlin is your clearance limit at the moment."
Now Dunshaughlin at 1000 is outside the control zone. So I'm not cleared into the zone yet. Broad meadows and obviously runway 29 are inside the zone, where I'm not cleared yet.
Now supposing the controller, being busy, didn't say "But Dunshaughlin is your clearance limit at the moment." Could someone take the rest as an implied clearance into the zone? What if the R/t was really busy as they got to Dunshaughlin and couldn't get a word in? Would they continue into the zone for a minute or two until they could get a word in?
The only way to deal with this uncertainty is to either ask the controller what they mean, or to express your understanding of that the controller has just told you. The only person that looks a bit daft is the controller for not making it clear the first time. If enough people ask, then they will start to do it properly and give explicit clearances like they are supposed to.
dp