How many dimples on an English golf ball?

They are the same thing, in the UK we do not have different types of Golf ball from US ones. There is no difference.

The smaller British golf ball was banned from being used in the British Open in 1974, so it was gradually phased out as it was illegal in all of the majors after that. It was 1.62 inches in diameter as opposed to the USGA standard of 1.68 inches.