As the other thread is a bit old (and poissibly out of date) I see no problem with 'current' battery ideas....
.... I have recently replaced mine as it wouldn't hold a charge for more than a day - so i did some research and went for an 075 (this is the size/shape designator), which is the 'newer' version of the 065 (which looks like an 027 to me!).
When looking, I noticed that they do a 'standard' 065/075 with 52Ah, or a 'High Capacity' with 60Ah and 570CCA.... it is Calcium Technology (which may well be superceded by now with some other snake oil contents), had a 4 year warantee and cost under £40 on my doorstep within 24 hours. (ebay special).
Fitted it the next day, and all well - then the day after, it was flat
Thought to myself "shouldn't have tried to save a few quid on a battery", and fitted the charger to see what would happen - it flashed an LED to tell me that there was a battery (charge) drain somewhere.... Oops - interior lights were on! must have been from when I was giving the car a good clean before Castle Combe, and went un noticed.
Still, looking on the bright side, I now have a new battery in the car, and a 'spare' one (which DOES hold a charge - but not if the lights are kept on!), and can use the car.