need help in knowing is job has been done properly

It's quite common to still see the beading on the corners and as long as the plaster is level the beading will disappear once you apply a few coats of paint. Based on what I've seen the gap is only left because it's easier for the plasterers as plaster that low will usually be hidden behind skirting.

The edges of angle beads should always be visible once a finish plaster is applied and a good plaster will clean them up and you should have a nice crisp angle. Once paint is applied this will then be covered, but will leave you with a contemporary looking square room. If there is a cellar or a void underneath your room then you can skim to floor, however if it is a solid floor then you must leave at least an inch gap to prevent damp from rising up your wall. Thanks Scott @ PlasterAce

Plasterboard must not touch the ground floor as the guys mentioned above it helps to prevent damp! But!!! If the walls have been damp proofed (tanked) by an expert AND the ground floor has been properly insulated and damp proofed AND the area between the wall and floor is sealed there is no reason not to drop the boards all the way to floor as the room should be fully damp proofed. Beading edge is fine and can be covered with paint, that isnt a problem! Hope this helps. Russ

Hi, Gap is intentionally left to isolate wall from floor. Damp will travel up the plasterboard/plaster very easily. A wooden floor will move and over time the plaster will crack if it is not isolated.