ᐅ Cover plate, rosette, wall penetration trim – what is this part called?

Hi dear forum members,

We have a downpipe that passes through the balcony slab, see photo.

We want to install a cover around the opening as a trim to conceal the pipe.

I’ve searched extensively online but couldn’t find anything. I looked for terms like rosette, trim, clamp, cover for downpipe or wall penetration. Apparently, it’s called something else.

The downpipe is DN60. Do you have any tips on what this part is called or where to find one?
It would also need to be two-piece.

Suitable stove/flue pipe rosettes are available, but only as single-piece versions that slip on, not two-piece. Since you don’t want that, what speaks against patching with repair mortar/quick-setting cement, possibly combined with sealing tape or a collar around the downpipe?

Hmm, that's unfortunate :-(
There’s basically no problem with doing additional plastering ourselves, except that the plasterer, who still has to come back anyway, is refusing to do it because it means extra work for him. And we’re not really confident that we can make it straight and look neat afterwards. How would the sealing tape work together with mortar or quick-setting cement?

Am I the only one who thinks that the opening and the overall workmanship don’t look very good? The pipe seems to be new or was recently removed. You can see the drilling dust on the wall around the spacer because of the paint... Remove the pipe and install a rosette over it. Anything else would require more effort, especially if the same people who messed it up are the ones doing it again.