DFC, your persistent view - despite being repeatedly told otherwise by those who intimately aware of the practical application of the rules that you quote - appears, on the face of it, to be a matter of differing interpretations of the rules. In reality, filed flight plans are normally addressed by ATS/AIS staff and not by pilots. Things are changing because pilots, for a variety of reasons, can now have access to the ATN messaging systems. ATS /AIS staff address FPL messages according to well defined rules and pilots should do the same. These rules DO NOT include addressing FPLs to units that you may just happen to be passing by.
In years gone by these rules were included in CAP493 MATS Part 1 but for some reason they were removed a long time ago. I guess if they were still there you'd be able to read them and quote them in forums like Pprune. As it is, I dont think they're published in any UK document and the only place you'll find them is in an ICAO doc - the reference for which escapes me at this time on a Sunday morning. But I'm sure you'll be able to find it!
If, after you've read it, you still think you're right, please tell us all why.
If you're right and I'm wrong, I apologise. If I'm right and you're wrong, don't worry about apologising, just learn that despite what you think, if everyone else who know what they're talking about is telling you you're wrong - then you probably are!