Metronome

Hi, at the plumbing of my bath (new build flat) it appears that the soil trap seal is only 2" (as shown on pipe) instead of the 3" 75mm seal that building regulations H require for a connection to a communal soil stack. Also they've dug out the screed to fit the pipes which doesn't look right to me, I would expect some sort of sub floor to have been added to raise the bath? If anyone can provide any information I would greatly appreciate it and see if it's something I can raise on my new build insurance with Premier Guarantee Many thanks