Pip managed to fall/roll down a little incline in the garden this afternoon in his haste to hang off Lurcherboy's beard. He screamed as if he'd broken his leg and wouldn't get up, then when I stood him up was limping badly.
I was beside myself, scooped him up, brought him inside and checked his leg, no sign of pain. Then, quick as a flash the little monkey leaped off my lap and shot off up the garden again. 
I should have known, Lurcherboy is a really big wuss when it comes to pain as well and it's quite common in sighthounds. His foster mum even told me about a similar event in their garden that really scared her.
I'm looking forward to the weekend and having dh home to tag team on watching him. Not to mention dh has said he'll do the night shift tonight and tomorrow, so I will finally get a decent span of sleep.
He's definitely improving. He doesn't scream when I'm out of his line of sight anymore and will happily trip off up the garden or the living room or kitchen on his own, so is clearly feeling more settled and secure.
Hoping to move things along next week a bit more quickly, as by September I really need him to be able to be left in his crate for at least 20 minutes without screaming the place down, so I can do the school runs. It would help if I could stuff a kong or give him a treat toy in there, but just being on white fish and chicken, it makes it a bit more difficult.