Could Anyone Explain Please
" .. could I fire both of these off camera with the 7D pop up? .. "
As others have said, your 7D built-in pop-up flash is a Light/IR Controller or Master unit. (And it effectively has its own 'Group' too - though it lacks HSS.) So for instance you could set your 430 to Group A & your 580 to Group B, then you could both control and trigger those units off-cam wirelessly (comms are Light/IR). The control from your cam's screen (flash menu) is either under ETTL or M (M being remotely adjusted M power fraction setting by Group).
See the Video Tutorials for the 60D Flash controller - the 7D adds group C control.
locate 'Integrated Speedlite Transmitter'.
.. not quite up to date, but still useful.
(Canon have moved on to their new 'RT' radio system - the 7D pop-up uses Light/IR comms.)
If you need greater controlling/master range or if you need HSS across the network, then you could use the 580 in the cam's hot-shoe (or OC-E3 or clone), set it up as 'Master' (NB defaults to Group A ) (it may be set to contribute to the exposure or not) then your 430 would be its remote slave. Cheers, Donald
Thanks a lot I found this most helpful, I have an idea now what to do thanks again