Fresh tomatillos in London?
I've seen tinned but if I'm going to substitute then maybe just use the dozens of green san marzanos in the garden? Also fresh Anaheim chilis - reckon the mild green long Turkish chilis will be OK? It's for a chicken chili verde recipe, thanks!
I've bought tomatillos at Whole Foods market in Kensington, but haven't seen them there in a bit (granted I haven't looked either).
There is a mexican stall at Borough which sells tons of mexican ingredients that may have the tomatillos, but should definitely have the chilis you need.