Fabulous! Thanks guys, now I know. But overriding all of this is the responses I got on the ATC thread (same subject) where the people dealing with FPLs made it clear I may as well just file say "DCT SAM DCT MP" even if I intend to skirt around Solent radar airspace and route via Portsmouth Harbour etc, and not to bother with more detailed descriptions of turning points as they don't carry much meaning for them!
But, as always, we can learn everything right here on PPRUNE!
Andy
