You've made me second guess my local pronunciations now.
I think Tesco's, because the L sound only goes on the end of the word, and Bristolians say Tesco's and not Tesco (which would make it Tescol). I'm prepared to be wrong about this though, as I talk like a posh twat in comparison.
( Aardvark and so at last, I understood, Thu 30 Jan 2025, 12:24, archived)