Whenever I enter our house through the front door, you can smell a garbage smell in the hall, you can't smell it anywhere else in the house and the smell seems to go when we've been in the house for a while, but then returns if we go out for a while and come home again, any idea what could be causing this? :confused:

This sounds a lot like the sewer gas problem I had. I don't think it actually goes away, but you get used to it while you are indoors. As for the source, I would look for nearby drains or traps that may not have any water in them. Check floor drains as well to make sure they have water in them.

Good Luck