UPDATE: Yes, the answer is Pomeroy’s. About which, for reasons of good beer we were prepared to overlook their devastating omission over the door of the necessary apostrophe .
By the way, if you’re visiting Christchurch and want something a bit more fun to drive around, I can recommend contacting Ron at MX5 Rentals—a fellow MG owner—for a sensible 2-seater Japanese car without a roof.
Tell him I sent you. (Who knows. It might work!)