Taylor Wimpey have form for
noise transfer including from flats above!
First of all please don't complete the 8-week customer satisfaction survey until Taylor Wimpey have sorted this out. In fact, when you write, tell them you will give a bad survey response if they don't sort it out.
Yes there is usually a void between the plasterboard and the PCC concrete floor beams. It can be insulated but I doubt this will prevent the impact sound noise you are suffering.
The floor needs to be isolated in most cases carpet and a decent underlay and reasonable neighbours is sufficient. Nowadays, laminate flooring and ceramic tiled floors make it more of an issue.
If you live in a timber frame block of flats, the floor will be timber and it will be even worse, especially if the upper floor is not fully isolated from the floor joists and walls as per required standard and robust details. If it is timber frames construction, you should also be concerned what would happen if a flat in your block were to catch fire!
Finally, often acoustic testers and warranty inspectors as well as housebuilders such as Taylor Wimpey, will tell you there are no requirements in the Building Regulations that cover "impact sound"
This is a moot point, as any sound transference is not acceptable beyond normal reasonable levels.
If Taylor Wimpey don't respond write to the NHBC.