Perhaps you know better than me, however I can't see how he can give you a clearance that is outside of controlled airspace.
Edited to add I've just checked the FAA interpretation to ensure this is not a UK issue.
See "AIR TRAFFIC CLEARANCE" in
A
AIR TRAFFIC CLEARANCE- An authorization by air traffic control for the purpose of preventing collision between known aircraft, for an aircraft to proceed under specified traffic conditions within controlled airspace. <snip>
Based on this the split controller did indeed give an incorrect clearance.