Only fixing toilet to floor and walls with silicone and no screws

[HumanAstronomer3194]

A four year old toilet in my parents house had a leak coming from the cistern, had to cut off the wing nuts to see the coupling plate was completely rusted. After cleaning up the area I add a new fixing plate with a new rubber doughnut but once I line it up with the wall I noticed the holes in the wall don't match up as the rubber doughnut is bigger than the old foam one. Able to source a foam doughnut which is the same as the old one and now only one hole matches up, put the spirit level on the cistern and it's level so I think it wasn't put on correctly the first time. Also two of the four the screws fixing the bowl to the ground are not going back in (they would bite for 1cm and go no further) which results in the toilet rocking and created a leak from the foul pipe if you lean forward.

A neighbour is a retired plumber so I ask him for his his opinion he says I've done everything correct even if I was being too particular about it and I just needed to re-drill the holes.

I had also contacted two plumbers one (has a 4.9 rating on Google) who called me back when I was in a wholesalers looking to buy a tile drill bit and plugs and he said he come over now so I drop everything and head back to the house.

He ends up silicone-ing the cistern and bowl to the wall and not using any screws (the whole reason why I had contacted him because I wanted holes drilled) and when I pressed him on it he said it wasn't required the silicone would hold it and prevent the rocking. He then charged me €170 for a 1PM call out which I thought was exceptionally high considering he didn't do the job I wanted him to do. If I had known he was just going to silicone the toilet I would have done that myself.

TL;DR, called out plumber to drill holes into tile over concrete walls/floor as I was too afraid of making another mistake and under pressure to complete the job before my father was discharged from hospital only for him not to drill any holes and just fix the toilet with silicone.

 

[blup]

I just sat the cistern on the pan when replacing them because I didn’t want to damage the tiles if anything needed redoing. It’s stayed liked that so silicone should generally suffice in a domestic environment. The weight of the pan keeps it in place with a bead of silicone round the edge, That said if you asked for the cistern to be fixed to the wall it should have been.

 

[Exedon]

Assuming the pan/cistern is now fixed solid is there a problem? (apart from cost and even that depends where you are in country)
We were long term new build subcontractors when fully tiled bathrooms especially with porcelain tiles became the norm fixing wc's with silicone bead under rim and through cistern screws holes became normal.
Done correctly they never moved.

 

[HumanAstronomer3194]

Assuming the pan/cistern is now fixed solid is there a problem? (apart from cost and even that depends where you are in country)
We were long term new build subcontractors when fully tiled bathrooms especially with porcelain tiles became the norm fixing wc's with silicone bead under rim and through cistern screws holes became normal.
Done correctly they never moved.

I'm just very much surprised a professional used silicone to fix the toilet. From what I've read online it does seem to hold up but it's not recommended. I would be surprised if it would be allowed on a industrial setting and would likely be flagged on a snag list for a new build no?

If a professional is willing to put his name to it then it must work but it's something I'd expect a DIYer to do and not a professional.

I'm also just annoyed if I known that this was going to be the fix I would have done it myself. The reason I called out the plumber was because I wanted it done to spec but I now know I would have done a better job myself.