You do usually get a period prior to completion where your snagging list should be drawn up between yourself and the developer. Most of the snags are then done before completion.
However, if it is a lengthy list then this could well continue. In my experience it very much depends on who the developer is - the bigger they are usually they tend to act a bit quicker.
I'll give you an example - I know of a builder (a huge national one) that currently have to rebuild most of an apartment block due to a lot of the building not being built correctly. The architects have gone back in and basically realised that the builders haven't done the job to their spec. The cost currently stands at £2m!!! All being done because somebody reported excessive noise on snags. They are just sorting it - simple.
On the flip side my parents bought a new build around 4yrs ago, they got to around 300 snagging items (some very major) and they are still trying to get them all sorted. Teh developer are trying to wash their hands, the NHBC are blaming the developer, local council & MP is involved etc etc etc its a nightmare and it's not a great deal closer to being sorted. The long & the short of it is that the house hasn't been built correctly, the developer apparently has a habit of settling cases like this on the court steps. I don't mind naming and shaming either cos they're a disgrace - Bett Homes (I think they are now owned by Persimmon).
It very much depends on who you are dealing with I'm afraid.
Do you mind telling who the developer is? (pm me if you prefer).