I won't lie: It felt weird to utter the phrase. For better or worse, over the years, I've tried to be aware of the fact that not everyone celebrates Xmas-and thus 'Merry Christmas' might be irrelevant. I've even taken it to the point of not buying 'Holiday cards' that overtly had any reference to Jesus, Santa, or anything that was clearly Christmassy.
So, when I got home from the market and told Simon about this-and about my previous behaviour, he effectively told me to get over it-Brits aren't that overly-sensitive about such a thing!
OK! Well seeing as how I'm trying to be as accomodating of the culture in which I live (said with tongue firmly planted in my cheek...): Merry Christmas everybody!