I totally agree things can get lost in translation.
I suspect the GP, nurses, consultants etc see 1000s of cases of severely impacted children a year. They all follow the same treatment plan. i imagine that as you get through the plan you've had you get less and less cases a year - most of us here have got as far as impacted and emema as outpatient.
So whilst to most of us here and of course, and more so to you, not passing a stool for 6 weeks and having a blockage seems like a complete medical emergency, it's possible the consultants see it 2/3 times a year and have done for 10+ years of their career so they are somewhat more relaxed about it.
I think it's easy for them to forget that as a aren't you don't know the routine, plan that's followed, outcomes, statistics etc. And it's certainly not easy just to sit back and trust the doctors.
It does sound though as if they have a a plan - sadly it sounds surgical as they sound like they are communicating that they've tried all medical interventions.
Try (and I get that sounds rediculous!) to get some rest. Ensure you have arrangements for DD1 next week, clothes and toiletries etc so if you get to Leicester and have to stay there you are ready for it and don't have to run around last minute organising stuff.
I'm so sorry as I ad this back and it sounds unfeeling and practical. It's just so hard to get words to sound as caring and reassuring as you mean them too. 