Ok, went to Gourmet Burger Kitchen today(different from Gourmet Burger Company? Probably).
The burgers were great. Really really really good. I'm pretty fussy about burgers, and had a bacon and avocado one (with cheese, for that double-treyf thing), and it was great. Really tasty. I don't know what all sauces were on there, but boy was it good.
The chips, however, were minging. Maybe better than Ultimate Burger? But not by much. Thick, at least. And their garlic mayo was alarmingly garlicy, and I like garlic.
I have realised, though, that part of the problem here is our local chippy. It's at the end of our road, and the chips are very good, and clearly made fresh. I just have to bribe them to make me a skins-on batch one day ...