Well i was clicking everything as you do and it turns out (apologies if everyone else knew) that in Settings\About if you then hit the light button on/off x 4 in a row about 1 second apart, you get a Development page, that gives you options to
: Force Crash
: Save RAM region
: Enable or Disable Bluetooth logging
: Enable or disable PTS Test Mode
. Works in Fenix 3 as well so I guess standard, and new home for the diagnostics as seems a few people by bad fortune did the old method which is without going to the About area first.
P.s. still working out the next step once there...
:)