After having a few electrical difficulties, decided to get an uprated car battery. (electrical problems when running a lot of things. HIDs + uprated bulbs all round fogs, reversing kit, SatNav etc.)

The recommended for my car is: 60-80Ah, 540-780A.
Currently running 55Ah, 525A. (255mmx175mmx175mm)
Fitting 72Ah, 700A. (278mmx175mmx175mm)

How exactly does the battery come out? Not picked battery up yet, so won't be doing it for a few days, but just want to prepare.

The battery is the same size height and width, but 2cm longer. It will fit, because there is a sliding clip holding it it place to adjust for different lenth batteries.

What i've got so far:
Disconnect negative, disconnect positive... then what?
Is the battery bolted in anywhere, or just clipped in?