You've done a good job so far. My suggestions are simple and are similar to others already made.
I would change the color and font style of your logo. Maybe making it a little larger and "cleaning" the lettering up would do. You want it noticed and easy to read, for now it reads a little "fuzzy".
I agree that the page orders should be changed. Maybe: Home, Why..., Areas ..., Tariffs, Contact/ Enquire, then Privacy.
I don't really see why you would need a "Contact Us" and an "Enquire" page. That would solve the no link issue and save confusion on the preferred forms of contact. I would refer to the tabs on your header instead of stating "see xyz link below"
Overall it's a nice site. I like how you thought to explain any tolls incurred from the calls. Helping you has helped me by looking at all these things we might be too close to see on our own. Major Kudos!!