What do you mean by "drop the rear beam?" (assuming axle?)
Yeh, unbolt to shocks and drop down the axle and slide the exhaust out as a whole.
Also, if i do cut it off whats the best method? and would i need to "drop the beam" when fitting a new cat-back if i cut it off?
I took a hacksaw to mine, try make the cut neat incase you wish to sell/refit. You would not need to drop the beam with an aftermarket cat back(usually) as it comes in 2 parts.
Another question. sorry lol. I need a new centre section, i presume buying a cat-back would sort this? (i have loose baffles in my centre section)
Cat back is everything from the catalytic converter back, so a middle pipe(centre section) and backbox.