I’m pretty sure that the big Episcopalian (=Anglican/CofE) churches here do the same. Although I’d be stunned if they called them “masses”. Is your mum “High Church”? I maybe understand the high vs low, but probably not.…That's definitely not the case here! My mum is very involved with her (CofE) church. She'd probably have a stroke herself at the idea of Protestant churches not having midnight mass on Christmas Eve and then a Christmas morning service…
Those who love to do the categorization of the eleventy-billion different denominations of Christian churches in the US pause, quill pens hovering over parchment, when it comes to the Episcopalians. “Hmm. Aren’t they just like Catholics, except with no allegiance to Rome? Can they actually be considered Protestant? Hmm.” In the US, Episcopalian churches are often regarded as the church of rich snobs.
As a choral singer who has no particular allegiance to denominations, along with a pretty unorthodox approach to theology, I just attend whichever church has a good music program.

