To add some depth to the process for those to still go through the process:
Step 1 - Getting the ICAO 24-bit address from the CAA:
For use on an unregistered aircraft
If you are using an EC device on an unregistered aircraft, you need to contact the CAA Infrastructure Section at NISC@caa.co.uk and provide the following:
Your contact details (Name, Address, Phone)
Type of Aircraft (EG - Paramotor, PPG)
The details for your EC device, including:
Make
Model
Serial number (on my Skyecho 2 this is a 7 digit number on the barcode sticker)
The CAA will then allocate the EC device a unique ICAO 24-bit address to enable it to be used on multiple unregistered aircraft without re-programming.
Step 2 - Aircraft radio licence application form (OfW585) - Via Ofcom.
Use this guide for the radio licence. Click to OFCOM
Some useful info from the CAA regarding the type of licence needed:
It is the responsibility of the user of the EC device to apply to Ofcom for the correct WTA licence. The licence required will normally be an ‘Aircraft (Transportable) Radio Licence’ that requires a formal variation by Ofcom to use without a ‘Flight Radio Telephony Operator's Licence’ or FRTOL. Guidance on this can be found at the website below.
www.ofcom.org.uk_aeronautical-licensing
I hope this helps,