I’m not from the United Kingdom, but there was a Hamleys shop in the city where I grew up. We did not go there often, but I remember how it looked, how it felt. Even looking at their logo makes me all nostalgic. Guess their marketing works well.
Obviously, Hamleys is one of the major toy shops in the world and it shows. You can find almost anything you can think of on their website: regular toys, electric toys, creative books, construction kits, clothing, and even sweets. I am not really into toys myself, but it felt nice to choose a gift for my little brother there.
The prices are actually not as high as I expected. And the delivery is quite convenient. A nice User Experience is important even for toy shops.
So I guess Hamleys stay in business for this long for a reason.