Amateur opinion.
I would be automatically classed as non-resident. It all hinges on whether my flights are deemed to begin or end in the UK.
Looking at the notes to the HMRC document on the third test it seems fairly clear that at least in the context of the document the operative word is "
trips" not "flights". As you said in your OP you seem to be doing trips that start and end outside the UK.
But whilst I hate to say it of course for real piece of mind you need professional advice.