I am in the process of replacing the toilet etc. in the cloakroom and everything seemed to be sorted until I tried to remove the old toilet pan. The holding down screws seemed to be covered with filler but a bit of chipping would sort that - or so I thought - there wasn't a screw. So, if at first you don't succeed, use brute force. Result a toilet pan in 3 pieces and a great big lump of concrete left. Instead of fastening it properly they had dropped the toilet pan on a heap of wet concrete about 4 inches high inside the pan so now I had to get my bolster and lump hammer out but it just bounced - they had certainly used good quality concrete and stuck it to the concrete floor so it wouldn't even crack off. Next method get out my circular saw with a diamond masonry cutter and cut the lump into strips then break it up. That worked but have you any idea how much dust that creates and how it seems to go through closed doors without any problem. End result I flattened the lump and put the toilet on it. Just for a check I checked the side to side level - and it wasn't. Checked the floor and that wasn't either. Task for tomorrow - set the pan support level using a not too dry mix mortar and leave it to dry (with the pan removed) Fortunately SWMBO is away (or is that unfortunately) as I had to clean up the mess. Thank goodness for a Dyson
Standard building practice. just had a look at the toilet in my cloakroom and it's exactly as you described, pan placed on wet cement and no screws in fixing holes, and I fitted it I believe it's done this way to make sure the pan is on level ground, mine is on concrete floor with ceramic tiles. So pan would sit across grouting lines so better to place it on half an inch of cement.