seagullsovergrimsby
#cpfctinpotclub
I'm not sure NISA and BEKO have obvious pronunciations. They're foreign brands and how the natives of the countries they're from pronounce them usually has little bearing on how we choose to pronounce them.
As for Amex, it's a portmanteau of American and Express, so it is correctly pronounced as it is written, AM-EX.
NISA isn't foreign , just northern (originally pronounced NEESA) and was formed in 1977 as a convenience store wholesaler (set up along the lines of a co-operative) by Grimsby supermarket entreprenuer Dudley Ramsden. Mr Ramsden is the Life President of Grimsby Town FC.