I would like a puppy so I suspect these would be quite rare at rehoming centres as they are usually older dogs
Not so. Bitches are often abandoned when noticed to be pregnant by careless and uncaring owners and mothers and pups often dumped when the owner realises how much bother they are and how much they cost to feed and so on, or pups are simply thrown out or left in cardboard boxes at the gates of rescues. Plus, for a variety of genuine reasons sometimes owners find themselves about to be made homeless or sent abroad or marriages break down or what have you when they have a pregnant dog or a dog with pups or even a still young pup without its mother.
Search all the dog rescues and also contact local vets who often try to help in difficult situations.
Also ask yourself if you really must have a puppy? I'm a dog lover (though these days due to arthritis which limits my walking capacity a servant keeper of cats instead of dogs though all the cats are rescues and one of the dogs was too when I had a couple of beagles long ago). Don't assume that you must start with a puppy to be able to train up the pet you want. Rescue dogs are often trained by the rescue or in some cases the ordinary family home which fosters them for the rescue. Rescues respond remarkably once supplied with a good home and owner, in fact they can often be the best of all possible pets because they are so appreciative of a good home. The dog you really want may not be a young puppy but an older puppy or young dog (or even dare I say it an older dog) who is right now sitting in a kennel in a rescue just waiting for that special someone to take them home.
Don't whatever you do buy a puppy online. It will almost certainly be from a puppy farm, probably carrying various diseases and already traumatised by the dreadful life it has lead so far. Never, ever, buy a puppy unless you can see it with its mother and assess the situation in which it has been reared and even then be very very wary. My beloved male beagle came from a very reputable breeder and I saw him and his siblings happily playing in a lovely warm and clean environment, but he was desperately inbred (I didn't know as much then as I do now!) and developed awful medical problems which shortened his life by as much as a third. His companion (and the love of his life - he hated being an only dog) came from the dog pound the day before she would have put down. She was obviously a young beagle, the vet thought she was about 10 months, but I had no other information about her. The dog loved her from the start and accepted her as the dominant dog in the household and followed her faithfully for the rest of his life! The initial few weeks were hard for me though because someone had clearly failed to let her out as often as necessary and then punished her for having accidents - so she'd ask to be out and then wee on the floor in a panic before I could get to the door. But once she realised I was never going to shout at her or hit her and I'd always race to the door to try to open it in time for her, it all settled down and she became a totally clean and reliable dog.
