The job sounds fine, but I’m not sure about the being paid well part. It isn’t neccesarilly little, but you’ll probably pay a chunk of income tax (I’m no expert on taxes in the UK, so I don’t know how much) and living in the UK is quite expensive.
I should make clear I’ve never lived in the UK, but have friends and family that do. Also, I make a similar amount (towards the botom of the range given) here in the Netherlands and I don’t think I’m considered to be extremely well off. Ít is more than enough for me though, but almost half my net salary is going to fixed costs.