The Skyway Code (V3) was published in March 2021 and is post-brexit material. The CAA advertise that (among other things) it:
- Reflects the UK’s departure from the EU and guidance on the associated changes
- Updates to all aeronautical information, including radio frequencies and frequency monitoring codes
- Radiotelephony exchanges updated to reflect latest CAP 413 guidance
Hopefully it can be of use (even if not specifically for helicopters).