The fact they are regustered with the local council suggests they have more than one breeding bitch and possibly produce more than one litter a year.
There wont be pedigree papers as they are cross breeds. Not of great import if you want a family pet.
You just have to swallow the fact you are paying over the odds for your pup. Thats how it is at the moment if you want a cockerpoo they are £££ sobe wary of someone cashing in.
You should be provided with vaccination details, it might be worth checking what vaccine pup has had as not all vet practices use the same so its good to know before you book for 2/3 vaccinations.
Pup should be microchipped and you will need to register this in your name. Its easy to do, just put # in petrac (or what breeder tells you) , there is usually a nominal fee for this.
A record of worming will also be provided.
A good breeder should be vetting you so be wary if they were keen to sell without asking questions etc.
It soundslike you are doing everything right.
Some breeders offer 4 weeks free insurance. I strongly advise you take this or take up the offer youre vet will likely offer you. This means youre covered from day one and avoid the nightmare of 'pre- existing conditions. This will require a vet check before you set up.
Pup will need its initial vaccinations this is usually two lots of jabs 4 weeks apart or three jabs two weeks apart. You will need flea and worm control monthly, again dependant on age and products used. Do not waste money on products sold in home bargains etc, at best, they dont work.
You must be very excited. Good luck with your new addition