Wish I could find the FRA Advice from March (?) 2020, but I can't.
I don't recall that advice trying to lay down any specific 'rules', nor anything as heavy-handed as that, as self-evidently that would be ridiculous if not also impossible to calculate re any risk formula for individuals. Rather, I recall it helpfully suggested that fellrunners were each mindful of their own limitations, capabilities, and took personal responsibility by acting accordingly. Least, for example, we had to call upon the MRTs and/or ended up occupying a hospital bed or similar at a time the NHS is under extraordinary stress. The same principle might be applied to your cycling example.