Kelly and I travelled from Sydney Australia to Scapa Flow in August 2013 to dive the German WWI wrecks. We used MV Radiant Queen and despite being an old trawler, she was in mint condition and run by the best dive operator I have dived anywhere in the world (I have almost 4,000 dives to date). The owner and skipper, Emily, knows more about the wrecks than any person alive without a doubt. In 2014
she had a new boat built, the MV Huskyan, which started operating last year. This looks fantastic and is easily probably the best dive boat in the northern part of the UK, if not the whole of Europe.
The diving was a lot easier than I thought, considering it is deep, very cold (for us), sometimes very dark, often dirty and with some currents. We took all our own gear and only hired a small pony for deco gases. We did not do huge bottom times, but had deco on every dive. The live boats was something we have only every experienced once, but was easy to get used to. As long as you are experienced at diving to 40 to 45 metres in cool water (under 20C), then you should not have a problem. The entry from such a high deck caused no problems and the diver lift was fantastic at the end of the dive. Kelly tried to talk me into putting one on our own boat .
Their accommodation is also excellent, only 100 metres from the wharf where MV Huskyan ties up.
As mentioned, most boats are booked out by a group. MV Huskyan is now probably totally booked out for 2016 and most of 2017, but if you contact Emily, she might be able to put you in contact with a group who has not yet filled all the spots. This is what we did over a year before we went.
One of the best diving holidays we have ever done (and we have been to Chuuk, PNG, Solomons, Indonesia etc).