@fandangored I would suggest you do lots and lots of research. So I advise doing the following:
Have a good look at what breeds are available. Consider what's important to you, eg energy levels, trainability, insurance costs, breed traits, potential problems. A good start would be the Dogs Trust guide here. Another way would be go to Discover Dogs and talk to loads of breeders about their dogs.
When you've got a shortlist of breeds you like (I know you like Cavapoos but they may not be suitable for you) find the national or regional breed clubs, go to their shows and meet more owners/breeders. You may also find the breed club rescues have suitable dogs which have proven family-friendly too if you want to consider a slightly older dog.
Google "how to find a reputable dog breeder uk". The top 3 results are The Dogs Trust, RSPCA and The Kennel Club
Learn about dog behaviour and training before you get a dog. You could ask your local vet for their recommended trainers/schools, then contact them and ask if you could come and observe. Puppies are a huge amount of work and you'll need to know what you're doing or it's easy to train unwanted behaviours!
Choose a training class in readiness for when you get the dog. Once you have the pup, go to the classes regularly. Do lots of training and careful socialisation outside of these classes too. It's a huge, tiring, commitment, but you get what you put in. And if you don't do your due diligence, or don't put the work in, you could have a nightmare on your hands.
Good luck! 🙂