I think you've handled it brilliantly insanity. Fingers crossed it all goes smoothly and you have a gorgeously smart boy at the end of the appointment. 
I am having a wobble about taking my two on the ferry next week after the incident with the Pug on the cross channel ferry last week.
I have been taking my dogs over to Ireland on the ferry since the early 90's with no problems at all and I know it was a bracycephalic breed, whereas my two have great long pointy snoots and hardly any body fat, but for some reason it has still rattled me. Just spent a fortune express ordering large window grilles so we can keep all four windows half down, a lock so we can lock the tailgate open to 18" and a cooling mat, then have a road refresher water bowl that clips onto the crate and we will be arriving early so that we can make sure they are already cool when we drive on.
Still doubting myself though and wondering if we shouldn't pay the admin fee and switch to a night ferry.
Don't think all the vitriol towards the Pug's owner has been helping really. As if they don't feel bad enough. I'm sure if they could go back in time and change things they would. So many people saying they'd never take their dogs on ferries - it has be doubting myself and wondering if I'm a bad owner for it. The dogs love it though - not the ferry, but the holiday and the freedom they get over there, they get really excited when we start getting ready to go - surely if they hate the ferry they'd get stresses and anxious instead?
In more positive news. I spoke with our neighbour yesterday and he said they don't hear our dogs at all these days. Huge relief as Pip was being a bit whingey on school runs the last couple of weeks and I wasn't sure if they could hear that through the wall - apparently not. So it seems his whiny whingeing noise doesn't travel like Lurcherboy's howling did and I can stop worrying so much about it.