Well, given they announce on their Pets4Homes page that they breed: Cavapoo | Cockapoo | Cocker Spaniel | Labradoodle | Miniature Poodle, I am not sure why you think they would ever be a good breeder.
Yep. Any breeder who breeds five different types of dogs is definitely someone you should not use.
Please just get a pedigree, OP. Gently, you clearly know nothing about dog breeders or the breeding industry as you keep selecting breeders that are patently puppy farms. Your friends 'lovely cockerpoos' were probably bought from puppy farmers and your friends have contributed massively to the cruelty and abuse of animals. I guarantee most of the cockerpoos you have seen out and about, are actually poodles - lots of people confuse them.
Breeding, when done right, is bloody hard work. That's why most good breeders don't have more than one litter every two years or so. It's soul-sucking. It's draining. It's utterly bloody miserable.
Go on the KC website. Look at minature poodles. Fully health tested only. Ask the breeder how many litters they have a year, or per bitch, (anyone who says more than one every few years or more than two a bitch should be avoided) and then go from there.
Also, if you insist on restricting yourself to 'around Derby' (as you appear to be) you are automatically narrowing your field. You need to be prepared to drive a long way for a good breeder - that or wait.