Hi, I obtained the game via Steam which for the UK is the best. However if you don't like Steam, you can buy it direct from Larian but prices will be in Euros. www.larianvault.com
There is no boxed retail PC version in the UK but there is in Europe. A member said if you buy the German version it also is in English but I haven't confirmed this so I'd check with Larian before buying a boxed copy. Steam is cheaper anyway.
As for the controls, it plays pretty much like a 3rd person shooter with the keyboard and mouse. I didn't play it with a controller and the dragon controls are pretty easy; move forward / backward / strafe with WSAD and aim where you want to go with the mouse. Note that unlike Drakan the dragon cannot land and you can't attack ground troups (you have to transform to human for that) but this feature should be in the sequel. The developer's mentioned on the forum that Divinity 2 originally had the ability to attack ground enemies but it had to be removed for technical reasons. Think it was because they had to make it an Xbox game as well.
There is a new(er) free demo on Steam so you can try before you buy. It is the intro of the game and part of the first map but it lets you try out the Dragon at the end. You will need to look for the dragon knight saga demo not ego dracons as that is the old one.