Growing up in the US and learning how to bake in the UK I’m pretty comfortable using both the cup form of measurement and measuring by weight. Personally, I prefer to weigh my ingredients in grams. It’s so hassle free and less washing up! It is hard and messy trying to measure a cup of butter is all I can say! This table is from King Arthur Flour. I converted the ounces to grams myself. Keep in mind that different brands of flour may weight differently.
A kitchen scale is a good investment. I found one on sale for £9.99 that weighs grams, ounces, milliliters and fluid ounces.