Oh lovely, replies! Thank you! I'm a realist planner, not an overthinker (honest!) 
I was looking at Kongs last night actually; had no idea they came in different sizes and toughness. I'm suspecting until I know if he's a chewer I should go with a large red or XL red? See, the questions just keep coming!
I'm relieved about the 2 hours not being a long time. I was reading about anxiety and over-reliance so getting the balance right is important. I dreaded the idea of having him in the car every time as it seems unfair.
The rescue centre has kennels if we go abroad. A friend surprised us by asking us on a short trip to Dubai in about a year (yes I know, not every day so said yes!) which I have already covered with a friend who wants a grey herself and already has cats saying she will house sit. Other than that we have no holiday plans. Tbh with Brexit I'm happier to wait it out and am unsure how pet passports will work considering the confusion about visas and driving licences etc.
Another recommendation I was hoping for was crates - i've read 48'' is a good size but varying things on wire or plastic and which brand? Does a crate actually fit into the back of a car? Mine is a small SUV type.
Most sites seem to say just to use a folded old duvet for the settling in period but the largest bed you can find after this unless you want them taking over the sofa
. I'm happy for them to take over the sofa - we have a large corner one which is never full! Want to also allow them to choose elsewhere so will have the crate up for a while and maybe 1 other bed spot downstairs. Any recommendations on whether they should have the raised "wall" around the edge to hide their heads?
Completely agree with the child gate. We were thinking of that just in case he decided to pilfer dd's soft toys. I'm more worried he would hurt himself on spikey bits (eyes or whatever) or choke on one of her small plastic tat items that take over her playroom. I think with the crate up he should feel secure enough alone downstairs overnight?
I'm so excited on one level but trying to consider everything that could be an issue ahead so i'm happy there is a group here willing to answer my weird worries! The weirdest one was possibly when I considered getting a child monitor for when I am in bed in case he needs a wee but doesn't bark loudly to wake me...
then I realised I don't' mind a few accidents and we will soon get into a routine. I'll make sure I take him out before bed.
With the enclosed open spaces mentioned, are there areas specifically for dogs like this? The centre goes on walks and holds events which will be nice to socialise etc, but I'd love to let him do zoomies and be more playful than a lead seems to allow!
Right, school run - thanks again for your help!