Nice one Ben, and good on ya for getting out on a cold day! Scenic area you live in, and looks like no shortage of trails to explore.

And yes, riding a mountain bike on the road is a slog. Slow-rolling tires, heavy fork...Gasp! Are your tires set up tubeless? That helps a lot to reduce rolling resistance and rotating mass (about 250g/wheel). I did that on my bike, and it is brilliant.