how do you go about vetting a new home for a puppy and what questions do you ask.

As many as you can, even better if you can see them in the flesh, and continue to speak to them as often as possible. Get them to visit the puppy and observe what they are like with it.
You will get a feeling as to whether they are right or not. Ask whatever you need to know, and dont feel that you are being nosey after all this is the welfare of your puppy that is at stake.
If you get a gut feeling they are not right even if they are there to pick the puppy up dont let it go.

Thank you LongDog for your reply.