Where exactly was your clearance limit when you were with Dublin? If you were cleared to leave their airspace to the east at say 4500ft, then clearance onto the airway is implied, as the airspace is contiguous, or else they will instruct you to remain clear.
I don't know about the clearance limit which isn't explicitly stated but Dublin can't clear you into UK airspace. They always dump you about 10 mi W of the FIR boundary with the 'wrong' London Info frequency 124.75 which doesn't work W of Snowdon. Usually you call Valley, or if closed London Info North.
I don't think any continuing clearance is implied. Maybe it's different under IFR?
There is no clearance under VFR - except for the immediate bit of CAS you have been explicitly given.
(Unless it's France, where they don't seem to worry, once you are in radio and radar contact, because presumably they know your route, etc).
Under Eurocontrol IFR (not the sort of IFR one does in UK Class G) one has an implicit whole-route clearance.
(Unless somebody has screwed up, e.g. French ATC handing you over to "London 124.6" instead of London Control - this is a classic).
Aveling, what I'm trying to say is that if you've REQUESTED for a DEPARTURE to the EAST at 4500ft and that clearance was GRANTED, then you could have flown a route that took you from the CTR, to the CTA and then onto L975.
Parts of L975 is within UK airspace but is delegated to Dublin. You then exit the airway as the base rises and its class changes from C to A.
