Yes I agree always has been above 5000 ft before you must fly hemispherical since the early 80's at least.
That said I just looked up the latest VFG guide which is part of my EFB package and on page 229 shows the new levels. Yes they have lowered it to 3000ft . God knows why but I will bet London to a brick it has been done by someone who either has never held a pilot license or if they have they have spent 99% of their time in airlines or military up in the flight levels.
Anyway there are some exceptions when OCTA .
1. the aircraft is at,or above,3000ft AMSL, but below 1500ft, above ground level (AGL) or
2. it is not practicable to do so or
3. if the aircraft is a glider in soaring flight.
4. when in controlled airspace ,and ATC has given you a clearance or instruction.
Point 2 is the important get out of jail card, for those days when the cloud base is low and the ground is not flat. or some fog and low stratus about.
Business as usual.