My PRs are not far away from yours, although I haven't run longer distances yet. I also struggle to get to McMillan paces. I know I need to build up distance and develop a base before I consider starting HM training later in the year. I don't have anything to add to the discussion except your approach seems sensible and keep at it!

Thanks! Hopefully well both see PR's this year! I did an easy run tonight at 10:27 average with 1% incline (confirmed by heart rate) so I think I'll stick to using the half pace ranges for my longer runs.