Had had a few days not feeling 100% (thought it was the inevitable just-when-getting-back-into-a-regime cold) but it doesn't seem to have come to anything. So gave this a try. Short of breath and legs felt a bit weak from the start, but it didn't get worse so managed to get the hour continuous I was expecting to have to bail on.
Orienteering substitute - not complaining about having to come up with one, given I had to google Sunday night what Level 2 rules actually were then I can forgive the club for not assuming they'd have the appropriate protocols back in place by this evening. 10 minute warm-up (literally! It's cold today!) then tried for 15-20 fast pace - but went too fast... doubt I could have lasted much longer anyway. Then a more relaxed pace back to the office