I personally, don't like UK rotties. In Your place I would look more to the continent. You can get great dogs from France, Germany, Belgium, don't know about Netherlands.
What kind of dog you are looking for? The modern rotty, the classical one? Temperament? You gotta have these things clear before you are looking for a dog.
UK basically has the classical type of rotties, maybe somebody breeds something else, haven't paid much attention. If you look up Crufts rottie ring pictures, you'll get the idea, the modern is not my type to be frank, they look way too boxer/bulldogish rather than rottweiler, I personally prefer something in the middle.
These ones are one of my fav so far: "ROTTWEILER von der Katzentatze"
Not too modern, great temperament (my breeder just bought one of her pups for canistherapyand is loving the pup)
Also vom Wilden Westen kennel is nice, my dogs father is from there, great temperament
not my type of dogs and very controversial, pure show i think
I suggest you to google the breeders, check their pictures, decide how does the ideal dog looks like and then gather the information.
Many breeders has just FB pages, check the pictures, google the dogs. There are many who has show dogs with no character and temperament at all. Or bad one. Stay in between. If you have any doubts just hit a message.
Also, check the local dog shows, go and see if any of the dogs draws your attention, go to talk with the owner, see how the dog acts, etc. I know I sound like a crazy dog person but as I hope to spend next 10-15 (or more) years with the dog, I rather do my home work. Before I got Aslan, I met his mum, went to the doggy school and saw how she is working and behaving, at the doggy school I also met her mum and siblings, literally made friends with my breeder and then decided that I want a pup from THAT bitch. And I trusted that the breeder will find the perfect match for her dog which she did, all the dogs has a great character, some are working dogs, and they have generally good health.