Question for 8.33 rules knowItAll

[Prop swinger]

CAA:

From 1 January 2018 if you need to communicate on an 8.33 kHz channel you will need to use an 8.33 kHz capable radio

In practice, you can only continue to fly with just a 25 kHz radio if throughout your entire flight you only need to communicate on 25 kHz frequencies.

From the CAA website.