@hermionelodge we aren’t having great success at leaving ours. It can be quite hit and miss and I can’t work out what does/doesn’t help as sometimes he sleeps or plays and then in exactly the same circumstances the next day may cry or bark.
We have pretty much cracked it when in the house though - this may help if you’re puppy is barking as she misses you - but if she is just finding her voice it may not!
I did LOTS of flitting from place to place at first, so sit down, they come and sit near you, wait a minute, go and eg put the kettle on, they follow, wait a minute, go and sit back down, they follow, wait, go and get a mug out, follow, wait, go and sit back down etc.... so just keep doing stuff and flit around the place within the same room. Eventually they start to realise you’re being really boring and stop following you.
I did similar in the end with leaving the room. Sometimes it’s just not possible, but for example in the mornings I started going for a shower, put my robe back on and go and get the lunchboxes out, ignore puppy, go back upstairs and get dressed, go back and make the sandwiches, ignore puppy, go back upstairs and dry hair, etc. So I basically kept checking in, making it super boring for him by not interacting at all but he could see I was still there and would always come back. Now he is fine and I put his food down and go up for half an hour getting myself and the kids ready and he is fine.
Really I need to do a similar version with leaving the house I think. But like you say life gets in the way and sometimes they just have to be left. It’s hard as I worry about creating a problem with separation anxiety but he also just needs to get used to it. Most people have said to me theirs just settled down in time. Good luck!!