Dh just back from the vets.
First off it seems Mr Pip has a respiratory tract infection, so that was eyedrops and antibiotics £70.00 thank you very much.
Vet thinks it's highly likely that Lurcherboy has it too and needs the same treatment - so that'll be another £70.00 for him at his appointment later this week. Not sure if that has any bearing on his behaviour over the past week, I know I'm a right grumpy cow when I've got a cold/flu, so it could at least have a bearing I suppose. Interestingly I did notice that Lurcherboy appeared to have a runny nose this afternoon. I noticed it, thought it was odd, then just assumed he had got hot all snuggled up in his memory foam bed. 
He was supposed to get his kennel cough vaccine this evening ready for us to start acclimatising him to kennels, but that couldn't be done because of the infection. We were supposed to taking him for a walk around the kennels next weekend, then leaving him for an hour while we have lunch at a local pub the next weekend, then leaving him for an afternoon (to include a good romp around their fields), then leaving him just before they close and picking him up first thing. Obviously dependent on how well he does at each stage. We need to leave him for 2 nights in May and another 2 in July so he has to get used to it. Annoyingly the people we've found to do dog walking also do house/pet sitting, but they leave the dogs for 3 hours in between walks, while they walk other dogs - so that wouldn't work for our two.
She's manipulated his leg fully and watched him walk and said he seems ok and there's nothing obvious, which is reassuring. She's going on holiday at the end of the week, so she said, keep an eye, see if we notice a pattern of specific times when his gait seems off and come back to her when she's back if we're still worried and if we want her to she'll organise xrays, but as it stands she doesn't feel it's necessary.
Finally the neutering. She doesn't want it done yet and she's happy to speak to the rescue about it directly if they want to call her - so that's a load off my mind. Problem is they have to call her either Wednesday or Thursday this week or it will have to be in a fortnight's time, as she'll be away. Dh is going to call the rescue first thing tomorrow to discuss the situation and give them the vet's details.
Apparently she couldn't believe how big he's got and told him he has legs like stilts! 
Lurcherboy is now in a big old strop because Pip went out without him - he wouldn't have minded a vet visit himself, as he absolutely adores her. Daft dog!