Thanks @readyforachangemaybe! Yes, it was rather stressful - I confess I allowed myself a 15 second cry and a silent wish that we'd remained blissfully dog free since we lost our old terrier in November. We didn't have to get another dog, we were finally free after 12 years of an aggressive, reactive, chronically poorly dog but oh no, DH wanted a new bloody puppy. 
But then I pulled myself together and hoped for an easier afternoon. 
He has a kong but doesn't really get it, no matter how easy I make it for him - yet surprisingly he's fine with treat balls which churn out his kibble when he pushes then around. Fortunately he loves his food so I can use his normal daily ration as treats for clicker training (I watch Emily of Kikopups a lot, love her!), and I've often hidden his dinner in layers of tea towels, in a box of toys etc etc. It never takes him long though. We do regular training sessions and he does a great sit, a reasonable down, a poor stay, and he can go get a toy if prompted. He's rubbish at fetch though and even Kikopups video is confusing! DH is doing some good work on fetch.
He has flavoured puppy nylabones, puppy teething chews/rings, a rope, and edible turkey nylabones (one of the tiny ones lasts him 2 days). He does love paper and cardboard so I've made him up a cardboard toybox with some cardboard rolls in it, an old slipper, an old bit of webbing tape etc - everything he thinks is forbidden, so he can "steal" them with no reaction from us. He still steals and piles up shoes if he can get hold of them, but he doesn't tend to damage anything.
We do interact with him frequently but he does tend to get overexcited and bitey, especially with tug games - if he gets carried away and too rough, we disengage (end the game and ignore him). Then he'll get the zoomies and rampage around for up to an hour, it's exhausting. Is it OK to let him play around with his toys by himself, without interaction, for any length of time? I can't be switched on every second of the day, I need to do stuff.
He can be soothed to sleep by sitting with me but DH is "old school" and thinks I'm just teaching him that he can only sleep on me!
But he's already improved so much, that I'm hopeful that he'll gradually grow into himself and become a pleasant, easy dog. He's just a terrier puppy at the moment right?!