Thanks everyone for the recommendations.
After much review research, I bought some RHA TrueConnect earbuds (I was going to buy some Cambridge Audio Melomania – but found a very good deal on the RHAs), come with four sets of silicon and three sets of comply foam tips – so finding a secure fit was easy.
I’m pretty amazed at the build and sound quality of these, I’ve got some Jabra 85h over ears – which are a step up from the Sony 1000XM3 for me, and some Phillips X2HR open back 50mm wired over ears – all of which are as good as you can get until you’re spending north of £500. And these wee bluetooth buds sound incredible, and hold their own, almost feels bad to use them for riding!
Pretty impressed at what you can get out of a single tiny speaker.