Bring it back to basics and managing the additional risk of spreading or being infected by COVID-19 virus while engaged in an Audax UK sanctioned event, and let's keep this to Perms/DIYs at this stage - acknowledging nevertheless that calendar events are at the heart of worldwide cycle randonneuring.
General
Do not travel/ride/leave home if you think you might have COVID-19 (variety of rationales for such a judgement, well documented)
Outdoors
Other cyclists:
* in group: no groups of more than the government allowed group number (6 in England); maintain SD when stationary or moving; no bottle/food/eqpt sharing; do not join group which already has 6 in
* alone: pass (fleeting closeness moment)
Pedestrians and vehicles: Pass
Taps: Wipe before and after use, and use cloth to avoid physically touching tap.
ATMs: Wipe before and after use
Indoors
* Pubs: Avoid
* Shop/garage/cafe:
# minimise such stops (by choice, and by carrying sufficient food and two bottles);
# wash ungloved hands with carried (or provided) liquid before/on entry and on/after exit;
# adhere to SD and mask wearing (latter not Wales);
# rely on COVID risk mitigation measures put in place by establishments for everyone, even cyclists; carry and use own lock: no sharing
# choose to sit outside if possible
Comment: Use of shop implies no more NB 'additional' risk to the rider or others in the shop than a 'normal' visit to a shop to buy groceries.
* Toilets: wash ungloved hands before/on entry and on/after exit; adhere to advertised COVID risk mitigation measures
Overnight stop (once 400+ audaxes are sanctioned)
* Avoid if reasonable or (DIY) design route to allow 'home' as option
* See 'Outdoors' and 'Indoors' above
As an aside the Audax UK 'Behaviour Code' says:
"You should wear a suitable face covering when required to do so, e.g. if entering retail premises. If you propose to continue cycling afterwards and find the face covering uncomfortable, you should dispose of it safely, or store it in a sealable plastic bag. If you need to use a face covering later in the ride, you should use a different new or clean one."
Given that a mask's function is to prevent transmission of an asymptomatic individual's viral load, it's not clear to me what merit there is to bag a used mask and not use it again. I expect a proportion of audax cyclists will use a buff anyway so that will be reused.