OK. This is where the fight starts.
I suggest everybody on this site downloads this to their phone.
If there is some kind of security on the door, then simply show it to them.
If they ask you for evidence or ask you what your disability is, inform them they are committing an offence by asking you as laid down in The Disability Discrimination Act of 2010 and if they continue, you will call the police and have them arrested.
If they refuse you entry, call the police.
When the police arrive, explain the situation. You do not have to tell the police what your disability is but make it clear you want the guard arrested.
Film all of this.
If all of this gets scuppered then go to here and cursor down to 3. and screenshot it, making sure you get the phrase 'if putting on, wearing or removing a face covering will cause you severe distress'
I think we can ascertain by you taking the time to protect every GODDAMNED INDIVIDUAL LIFE ON Earth ......that this situation is causing you 'severe distress'.
Only by playing these cunning, evil, satanic, psychotic, would-be-despots at their own game, can you hope to be the light that illuminates the way for the rest of the sheeple.