Thought I'd let other people know just in case they were curious or looking for a new battery themselves.
I've decided to go with a "Super Charge - Gold" battery instead of the AC Delco, reason being is the Super Charge Gold MF75D23L has more CCA's (Cold Cranking Amps), the AC Delco in the S55B24L has 440 CCA and the SC Gold has 610 CCA.
Both batteries are also sealed and no maintenance and also the SC Gold comes with 3yr warranty where as the Ac Delco has 30mths (2.5yrs).
So for the extra price of $19.10 you get another 270 CCA's as Coventry's price on the AC Delco was $119+ GST = $130.90 (ordered in) and the SC Gold direct from Super Charge in Bayswater is $150 (in stock) usually $169 at Auto1 etc.
Here's the link to the SC Gold:
Supercharge Batteries - Car Batteries, Maintenance, Expanded Grid Technology