Do not insult the Devon and Cornwall constabulary by saying by saying they would employ Mr Cruise or that they would say "show those Oo-arrs" a thing or two - because a fair few of that force are those same "Oo-arrs"
Next, the Lands End site is a private site and repainting decisions are the fault of that (London based) company. The rather tatty archway is not a protected structure and if they had wanted the company could have painted it sky-blue pink with purple polka-dots, At least they did keep the Black and Silver colours.
Now the Cornish Language - which version? The stuff taught round Camborne/Redruth, the type preferred in St Austell or the version from the Padstow crew? Let me give you a hint - none of them are "Authentic" because Dolly Pentreath lived in Mousehole and died in 1777. No-one since her has spoken Cornish as a native or even first tongue and for more than 150 years no-one gave a tinkers curse. Living and working here I can say (with some certainty) that the vast majority of native Cornish have not the slightest interest in this tongue and they believe that most of those learning it are Grockles or Emmets (neither of those words is Kernowek in origin, BTW).
St Piran's flag, I agree a bad decision by the Olympic Committee but it had no practical effect. Certainly the roads from Penzance through to Falmouth were lined with bunting of black and silver and black and gold. I suspect that the real problem was that the flag has been adopted by Mebyon Kernow (a political party) as their symbol. I did hear from a Stannary member that MK had once wanted to use the arms of Cornwall but that was - err, vigorously - squashed by the Stannary Parliament people; certainly there is no love lost between them.
Finally, the "Met" does not police Cornwall. They may have supplied a few officers "on loan" but so might Bristol or Birmingham