we all know about 260 Margo (we only ask because it is normally below economic height there!)
Hmmm, interesting. It undoubtedly is below economic height but not by much if the 'when ready' descents are anything to go by. Of course it differes from type to type, airline to airline but also within airlines on the same type. However, most of the time we give an unrestricted descent to FL260 we see the a/c leveling off just a couple of miles after MARGO anyway.
Now, 260 level by Newcastle for Glasgow inbounds is a different matter...