But I live in a village with a small village shop, run by a couple in their 70s, one of whom has cancer. They don't let anyone in the shop without wearing a mask. And I think everyone should respect that. Their vulnerablility is very real and it makes no difference to their risk if the non mask wearer who goes into the shop is a covid denier, has asthma or is disabled.
It makes a helluva lot of difference to the would-be customer though! The covid denier can suck it up and wear a face covering even if they think the whole thing is a farce. The customer who is exempt because they cannot wear a mask doesn't have that option. The EA applies to village shops just as much as it applies to huge supermarkets and in some ways it's even more important because there may be no other shops for miles around, so the disabled customer cannot easily just take their custom elsewhere.
What they should do (and I have no idea if they do) is make sure they offer a service so that orders bacn be brought to the door to be collected by those who can't wear a mask. Then everyone is provided for.
This would only be OK if there were no alternatives that would allow disabled people to come into the shop like everyone else. For example, a perspex screen would more than compensate for the small additional risk.
From the statutory code for sevice providers:
7.4 The policy of the Act is not a minimalist policy of simply ensuring that some access is available to disabled people; it is, so far as is reasonably practicable, to approximate the access enjoyed by disabled people to that enjoyed by the rest of the public. The purpose of the duty to make reasonable adjustments is to provide access to a service as close as it is reasonably possible to get to the standard normally offered to the public at large
www.equalityhumanrights.com/en/publication-download/services-public-functions-and-associations-statutory-code-practice
Really though this couple are placing far too much faith in face coverings. If they are very vulnerable they could consider taking everyone's orders at the door. That would be much safer and would not be discriminatory.