A couple of web links to 433Mhz in uk,
The term used is SRD ( short range devices)


https://en.m.wikipedia.org/wiki/LPD433


https://www.ofcom.org.uk/spectrum/r...mpt-radio-use/wireless-telegraphy-regulations

To check it's frequency you need a Spectrum Analyser, or frequency counter.

 

I'm not condoning doing anything criminal like changing frequencies, but like a lot of these laws, littering, using a hosepipe without a check valve etc., etc.The devil is in the enforcement. Unless someone knows better, I bet you would have to back a long way to find the last successful prosecution for swapping a resonator. Radio Caroline might have been the last one.

 

To check it's frequency you need a Spectrum Analyser, or frequency counter.

I tried a frequency counter but It did not appear pick anything up, maybe bandwidth related so probably going to need a Spectrum Analyser.

 

cut the tip of your finger off and glue it to the resistor with a bit of super glue!

 

cut the tip of your finger off and glue it to the resistor with a bit of super glue!

Necessity is the Mother of Invention or You've put your finger on it.
Joking aside, probing a circuit with a finger can give you a lot of clues, assuming less than 12-V.

 

I'd like to be able to modify the circuit so it was tuned properly but wouldn't know where to start, as it's a low output with limited range I'll stick with what I have as it does what I want.