Milky we took ds to our first one. But he was only 5 months. I would potty take dd ( who's 20 months) if she's in a good mood.
Hasn't ever take. Us long. You go in, they ask you questions about why you're there, what kind of bleeding, when etc, send you for scan, get scanned, and back to epu where they talk you through the scan results.
It's more waiting around than in the actual appointments. Though if your hospital is anything like mine they'll have toys in all the waiting areas.
We book in at 8-10 weeks. With ds I didn't have blood test at booking in - because it was 4pm on a Friday so my blood would've been there till Monday. So they did the whole lot at hospital on scan day.
With dd they did it at booking in. Then just the ones that go with scan at the hospital I think.
So I ended up in hospital last night
because to save dd from burning herself on some literally just out of the pan gravy I knocked her back and tried to stop it and it landed on my wrist 
sitting in minor injuries for 3 hours in the most uncomfortable chair ever, with a burnt wrist and gradually getting more hungry and sick wasn't fun.
Luckily The kids stayed at PiLs while dh took me, then he went back to take the kids to bed, then PiLs just sat round ours until we got back 