Thanks for all the advice, very useful indeed. I like the sugesstion about using different sounds from different amps and guitars to fill things out. I've tried this to some degree in the past and it has sounded pretty good.
We have the ability to record everything ourselves. The plan once we had achieved a good sound doing that was to then go into the studio with all the recorded tracks and mix and master them with the help of a good engineer.
All this is pretty new to us so we're just trying to make the whole process as easy going as possible (recording at home, not thinking about studio costs etc). Hopefully all will be good.
Cheers again.