ADS-B Transmitter Registration Problem

Recently, I am building a system that using R820t receiver to receive ADS-B data send from a SkyEcho transmitter. According to UK law, I must apply for a licence to send out ADS-B signal on 1030 MHz band. Some people has claimed that it is possible to use ICAO address 000000 as a testing aircraft code without a licence. Can anyone prove this with related information?

Or can anyone recommend me any method that I can detect an aircraft without licence?

Maybe you could use some SRD band with the given limits of signal strength and duty cycle. Look for technologies for the 868MHz band like LORA.

Many thanks for reply. Getting research now.