The best way to fill round this (new shower waste pipe put through stone wall)

[ShowerWoe]

A plumber or his contractor did a new shower install.

In order to lower the ground floor shower tray, a new hole was core drilled through our stone wall; it also carved through flaunching on the outside of the wall.

When I inspected the hole after, it looks like most of the core dust had not been swept away; something gooey (silicone??) had been deposited, with what I assume is some stone dust to disguise it. See picture above. I don't think it's a good job.

I swept away the dust to get a better look, now I'm left with a space that needs to be properly filled. See picture below.

What do you think is the best way to do this? I need to stop water sitting in the carved area and vermin getting in.

How would you shape it around the area it's carved into the flaunching? What filler?

Thanks for looking

 

[Wayners]

I think using a waste pipe liner is better but they are rare. Can't say I've seen many in the wild.
What you have is the normal way I see pipes.
Sometimes fire foam around.
I plan to fit a new kitchen waste going out under kitchen sink so will use a liner and either cement around liner or use clear mastic

 

[denso13]

Coloured mortar or silicone would be fine.