Warm-up of 2.3kms, then started my threshold run. A 6.5km outward section, then turned at the castle, running back another 6.5kms. I finished the 13.0kms in 44:44 (3:26's). Felt slower than that so a little surprised by the pace. An improvement of around 45 seconds when I last did this session 2 weeks ago. They may be due to fresher legs though I didn't feel that fresh today.
Finished up with a 2.2km warm-down to give me 17.5kms for the day.