That’s a traditional schedule for ESB. The beer should be balanced despite the ‘bitter’ description. As far as amounts- hard to tell without knowing an AA% on your bittering charge. Williamette is a good choice for bittering. And now on to UK goldings. Goldings is the type of hop. If it’s grown in East Kent, then they’re East Kent Goldings. UK goldings was essentially grown in UK, but not East Kent. I’m willing to wager that you wouldn’t taste a difference.