How old are your cans ?!?Boddingtons cans are steel.
I'm not aware of any plant in Europe still running steel - Spain converted in the last couple of years. Big thing at the moment is down-gauging - thinner and thinner aluminium. Causes havoc until you get things dialed in . . and then some clown changes something, runs less lube in the bodymakers, plays with redraw clamp pressures . . . or just tries running too fast with machinery originally designed to run much thicker material, a lot slower.