If you're talking about green chiles rather than jalapenos, you're more or less out of luck. I found some (not Ortega brand) once in a fancy food shop in Belfast, £1.99 for a teeny can, and they were nasty. Even the Mexican mail-order places don't really have anything that I've found.
Best solutions I've found are a) import them and b) buy fresh from South Devon Chilli Farm, roast, and freeze. The fresh ones aren't very hot in my experience, but I brought back some powdered Hatch green chile that I'm hoping will help.