bath height

Hello, First post from a long time admirer of the site! Our plumber has fitted a bath (400mm internal height / deep). It feels quite high in the room (the edge is 600mm off floor). So there's approx 200mm under the bath. Wondering about having it lower, so took a look at the plumbing stack...

In a complete bathroom rebuild, my bath has just been replaced in its old spot (well, the new shower enclosure is 30cm wider so it is 30cm to one side of its old spot). They have put the bath's feet on bricks so they could attach the waste - so the whole is now at least 7cm higher than it used...