I recently complained to Natwest that one of their ATMs in Cardiff didn't have Welsh as an option. They replied really quickly (it was on Twitter) to say they'd sort it. I shall, of course, be going back to check.
My husband (who doesn't speak Welsh) and I have also taken to using the self service till in Tesco yn Gymraeg. It did seem a lot louder than the English, which I actually prefer - it got me some slightly confused looks from my fellow shoppers. Consider their awareness raised