I now have 8GB of ram in my server, so bare that in-mind when making recommendations on how much to up settings.
Basically, Apache won't concurrently load more than one page at a time. What the hell could be causing this? This causes real problems when I execute a page that takes a long time to load, no other pages will load.
Total idiot here, so advice desperately needed!
Thanks guys, must be something quite simple.
Problem solved, changed memory usage in scripts.