The song talks about the English rather than the British; a lot of people around the world tend to conflate the two terms.Wasn't it the UK rather than England? Language like putos would cause outrage if it was used in the UK, I believe it's more of a homophobic slur than putas which is witches/whores/sluts. I wouldn't repeat the definition I think it is, the sun stopped using that language a few decades ago.
Puto is actually incredibly difficult to translate - as an adjective it's not homophobic, but as a noun it can be (puta is the same, mildly offensive as an adjective but a lot worse as a noun). It's also used to mean coward, the same way cat would be used in English.