I sometimes wear white T-shirts. I don’t know if my Red Wing work boots would be mistaken for Timberland. Probably not since my work boots are also cowboy boots. But not for dining after 8PM? Sounds reasonable to me.
Although I generally eat by 6PM and never in a pub of any kind.
I'd probably fit in there as I tend to be overly formal in my attire. I wear white T-shirts, but only as an undershirt. I would never go out in public with just an undershirt as a shirt. It may have worked for Stanley Kowalski, but not for me.