Re: Proper Full English
On this side of the pond, Tetley comes in green tea, black tea, English blend, orange pekoe, Earl Grey, premium bland, original, you name it. I might find PG Tips at an import shop, like a Scottish store.
English Breakfast Tea is a black tea blend, which I like. The default tea here, including Tetley is an orange pekoe blend which I can't stand.
What I regret not trying when I was in London/Maidenhead is the white and black puddings. Everything else is easy enough to find anywhere.