Radio Caroline, on a community radio licence, has to offer a distinctive service from licenced analogue commercial radio stations in their coverage are, Music policy in their key commitments.

The main type of music broadcast over the course of each week is: rock music, featuring a mix of
album tracks from 1960 to the present day. Emerging local bands also feature.

Rock music has a wide definition
https://en.wikipedia.org/wiki/Rock_music

Here's Ken Bruce welcoming Tony Christie back to Greatest Hits Radio last February.