Silsoe ..i agree with your first point ...it is one i have been making so no surprise there !!
As for a chip re PPL v CPL .....as a CPL i am generally sticking up for PPL,s .......so how does the chip work ? Do i wish i had a PPL ? Well i have one AND a CPL !!! As for Mil ...well most of my best pilot friends are Mil and give as good as they get !!
You still havent pointed out how it is dangerous to dive and fly on the same day .....but to answer you ...i dont think it would be dangerous if you know how deep and long you have dived and then how high you will be flying ...and as sport diving doesnt require any decompression i think it would be totally safe to do both !! ( let me know if you find out otherwise but i do know that diving accidents are often transported by helicopter low level )
As for GSM .....( A heli crop spraying company that was based near Ripon ) I had a lot of fun helping run it and managing the "Egypt Operation ". Things were nicer in the helicopter world in those days ...less traffic , less pilots with less rules and less egos . Only good thing i suppose is that it is safer today and more professional .