The service will launch on June 8th next year. It will be a two-class service on a Airbus A330 with 22 business class seats. Etihad already has a successful regional service from Manchester.
This is not the most efficient route, however, since Etihad has distance-based redemption pricing and I estimate it would a touch over 100,000 miles for a business class return.
Far cheaper is to redeem American Airlines miles. This is one of the biggest bargains in the hobby – American charges just 60,000 AA miles for a business class return to Abu Dhabi from the UK. Whilst Etihad is not in the oneworld alliance, which is why you cannot redeem Avios on Etihad, the airline does have a special partnership with American.
It is worth keeping an eye out for another sign-up promotion on the American Airlines credit card (a 15,000 mile bonus has just ended). Alternatively, if the 20,000 point bonus comes back on the Starwood Preferred Guest Amex it would convert to 25,000 American Airlines miles. With a little bit of card spend that is enough for a one-way on Etihad. Coming back, you could use Avios on the Qatar service to Edinburgh.
Note that Etihad generally caps redemption seats in business class at two per flight so this is not an option for families.