I’m in the US and can get lamb at fast food joints. Go to any Mediterranean shop for a gyro. Afaik it’s even more available in the UK since it’s primarily sold as people food, not dog food like the US market.

A joint of lamb is a special occasion dish, but I think the statistics are skewed by the massive number of drunkenly-consumed kebabs

Shepherd’s pie is a fairly regular Sunday meal.

And kebab meat is normally lamb. You can get that at pretty much any takeaway chippy in the country, and is traditionally eaten with about six pints of cheap lager.