Culturally British? Yeah that makes sense, being muslim was never an issue. I would tell them, even my boss and his dad, that they're a bunch of hypocrites (look down on drinkers yet happy to profit from it, loved gambling on a variety of things) and laugh at them when they were waffling about the Quran says this and my imam said that - flying carpets, weeping statues, men as big as dinosaurs, fasting etc. They were never offended.

Have the same harmless conversations today, even if the muslims aren't bothered you'd have a bunch of middle-class SJWs reporting you for racism.