Bog-standard D54 is that.
It's not so much whats happening at 'this end' as what it's being attached to at the 'other end'. In other words in a lot of cases they will dig down to the existing D54 in the footway and then fit a swept tee to take the new duct it to the premises.
That's exactly what they did here from what I can tell. I wasn't able to snap a pic while they were working, and they'd already got the tee in place when I got home, but they'd dug down about a foot to get to the existing duct - which luckily was exactly where we'd hoped - and fitted a sweeping bend somehow over the top of the existing duct - I guess there is a way to do that (maybe they have a tee that splits in two, or has a slit up the back and clips over existing duct?)
Chap said it was a really nice job for them to get, just a little bit of digging in nice soft ground, and everything where they expected it to be. It only took them a couple of minutes to get the pull rope in.
I'd expect it to be full of water by then.
Perhaps, though the guy said it really doesn't matter and I'm inclined to believe them. The chambers built at either end is nothing like sealed - you can see dirt in the bottom of the chamber. I guess I could nip out and put a cap of some sort on it, but the water is likely to just run to one end or the other (or perhaps accumulate if the duct bows in the middle).
He was more concerned about the possibility of mud getting into it, which was the reason it was left tall, he said the next engineer can cut it back a little if they need to.