Just smashed my Parkrun PB! 20.28! Over the flipping moon!
Bearing in mind that the route is slightly over distance (according to my GPS I did an extra 65 metres today, which took 11 seconds) and there's a bit of a slope in the middle of the circuit that doesn't seem too steep but is deceptive and I reckon adds on about 10 seconds per lap (the course is two laps)... I reckon I could definitely do sub 20 minutes on a flat, accurately measured course. Really chuffed with that performance though - it's at least 15 seconds off my old PB.
I reckon shedding a few more kilos would definitely help too - I'm about 69kg at the moment, which is a healthy enough weight, but I'm aiming for a "race weight" of 64kg, which is probably enough to make a difference to my time, especially on a non-flat course. (And would help me get up hills faster on my bike too, of course.)
Edit: according to Strava, my actual pace was 4.03min/km but my grade adjusted pace was 3.58min/km. I'll have that!