I'm in the UK and good value is harder to achieve on the .co.uk domains. EnglishNames.com would imo be worth low to mid xxxx range as a domain on it's own. A developed site would increase the value considerably. For example there is a massive chinese market for english names.
The market for English Names is mainly for countries outside the UK. Here in the UK, most people wouldn't be looking online for specifically 'English Names' as it's just something we'd already know. If that makes sense?