Your Dynaudio speakers are only 85dB sensitivity. The Raven is an outstanding amp. I have The Blackhawk, and would wholeheartedly recommend either Nighthawk or Blackhawk as your "end game" amp.
Which to do first, hard to say that it matters. Your Dynaudio are only 85dB sensitivity, which is very low to be using with the 20W Raven. HOWEVER, we had some 87dB speakers here and running with my Blackhawk in my room (bigger than yours) they CAME ALIVE with the Blackhawk! We had no problem reaching a very satisfying volume level. So if you do decide to get the amp first you can look on the bright side and finally hear the Dynaudio sound their very best. Just bearing in mind having to crank the volume up a lot and not listen to them "loud" loud but just pleasingly loud, if you get my drift.
Then in terms of speakers if you can match the Raven up with Tekton Double Impact, now you are talking some incredible good sound for very reasonable money.
Downside of doing speakers first is like this. The Raven will make your current speakers sound fantastic. But the DI will not make your amp sound fantastic, or anything else for that matter, they will instead let you hear exactly what they sound like. Which may not be that good. But a lot of people hear the sound coming out of the speakers, and credit (or blame) the speakers.
So brace yourself for the reality that your big speaker upgrade (if it is to good speakers like Tekton) reveals as many faults as strengths. I have seen it before, people blame the speakers for the stuff connected to the speakers.
Also the backlog on a Raven is way less than the waiting list on Tekton. So you can get the Raven now, then order the DI and by the time they are ready you will be too?
The only other amp I could recommend in your situation would be the Decware integrated. But Steve's wait list is a year+, and his amp is low power and so absolutely needs you to have the high sensitivity speakers first.