Soundproofing ground to first floor

[livvyliv]

We have recently bought a house that had a 2 storey extension done a few years ago.the problem is they didn't spend the extra £200-300 to soundproof the rooms(ground to first floor)
What's the best way to fix it?ive had a builder in who's advised to put a new ceiling in which seems quite a big job and messy.has anyone got any other suggestions/advice?do soundproofing panels work or can you lift up the floorboards and add insulation?
Any advice greatly appreciated.the kids running around up there sound like bloody elephants

I've used foam-backed chipboard like this which is laid over an existing floor and deadens footsteps and impact noise (not very good on air-borne noise such as music).

are there carpets, or has it been left with noisy bare boards or noisy laminate?