Cementing in around soil pipe exiting around brick wall. Is this required?

I've had a loft extension done on my house, all has gone pretty well. The last snagging point was that I spotted that the soil pipe hadn't been sealed in where it exits the wall. The guy on site put some expanding foam around on the internal wall so you can no longer see daylight from the inside, but they've not cemented in around the pipe on the exterior wall, and they are saying they don't need to.

The hole they have cut is a pretty good fit for the pipe, so it's not a huge gap (it's actually quite hard to see a gap from the outside) but it looks to me like cementing on the outside is a pretty standard thing to do.

I'd like your opinion on whether I need to push back on this. Is there any chance of water getting in to the brick work?