Well, it looks like a nice destination for me. I always understood Jersey and Guernsey were a "no go" for my microlight, given they're in controlled airspace; but Alderney is apparently feasible. Would there be any caveats in a flight from Cherbourg to Alderney? Seems like a short hop only? Don't even need to carry a raft! Customs issues, perhaps, or at least formalities?
Alderney is in Jersey zone just like the other two, but I've certainly seen microlights there, so it may be there is some formality to go through but it clearly can be done. You would need a radio for sure and ideally a transponder.
Arrival from Cherbourg is simple (with a flight plan of course), route between the two nuclear installations at Cap de la Hague and Flamanville, you'll talk initially to Jersey zone who will quickly pass you to Guernsey approach and then Alderney tower. They'll park you on the grass and you pay the modest landing fee at the office by the firestation where you also fill in the customs forms and then off on your merry way :-)