Re cruising levels - quadrantal is gone and UK now follows semi circular, as does pretty much everyone else. From the UK CAA website :The semi-circular level system replaces the quadrantal system and brings the UK into line with ICAO standards applied elsewhere around the world. VFR and IFR aircraft are allocated different levels to fly at:
- IFR flights use whole 1000's of feet (e.g. 1000, 3000 etc. when flying eastbound, and 2000, 4000 etc. when flying westbound)
- VFR flights use the intermediate 500 ft. levels (e.g. 3500, 5500 etc. when flying eastbound and 4500, 6500 when flying westbound)
For VFR flights, compliance with the cruising levels remains good practice but is not mandatory.