Makes me p!$$ed off just reading this! Sorry to see this kind of thing. ...and a Brooks!
I'm lucky to be able to bring my ride in with me at work. My boss even gave me a spot to build a personals cabinet in the warehouse so I wouldn't have to drive in with all my trucking stuff.
When I'm going elsewhere, like Home Depot or Wal-greens or whatever, I walk in and ask to bring my bike inside. Haven't been turned down yet. If it ever happens. I'll ask the manager if he wants my business or not - I can always ride to the next establishment.