Although it was published some time ago, I would thoroughly recommend getting a copy of "Where to watch bird in Ethiopia" https://www.amazon.co.uk/Ethiopia-Gabremichael-Julian-Francis-Spottiswoode/dp/1408130750. This is possibly the best birding site guide I have ever used.
Along the lines suggested by cheshirebirder, you might look into hiring a vehicle either with a guide as driver, or at least a driver who knows the birding sites. Ethiopian Quadrants should be able to organise this.
Right, I think I'm reluctantly going to postpone this trip until the next February: ie 2020.
Air fares seem to be on the up - and Ethiopian's direct Manchester - Addis have seemingly sold out.
I've looked into logistics a bit more: and I think 8 days on the ground is pushing it to do even the sites I wanted to do.
So, I'll put this out again earlier next year (c. August) for the following February, and for two weeks.
Road improvements continue apace - and it will be possible to do Ankober-Awash without returning to Addis.
Two weeks will be enough to do the Jemma Valley areas, Awash, Bale via the Rift Valley lakes, and further south to Yabello.
This would mean almost every endemic and most near endemics, and mean less stressful travel.
That would be great, thanks very much Daniel.
Who are you using as a driver?