Craig - you've now had TWO people telling you of problems caused by incorrectly specified lower capacity batteries - and those problems were CURED after fitting the correctly specified battery. I really don't understand why you don't listen to and accept that factual advice?!?!?!?! 
If your engine blew up, and you had to get a replacement engine - would you fit, say, a 1.6 litre engine (presuming your car is a 2 litre GTI)???? No, so why are you appearing to accept that a lower spec battery is OK?
WHO sold you those incorrect batteries? You need to take them back, and get a FULL refund - the Sale of Goods Act (SOGA) states that a product must be "fit for purpose" - the batteries you were supplied are NOT fit for purpose. 
Just stop fannying around, get the correct spec battery (I would personally recommend a Varta E44 - which is a 77Ah with a five year warranty) and your problems will be solved.!
For a start.... There is no need to have an attitude!
Sorry, don't mean to have an attitude - I'm having a sh*t day, and was a tad frustrated you appear to be ingoring the issue of an incorrectly speccd battery.
Secondly... Exide batteries have a good reputation and I know many people who use them so that is just your opinion.
It isn't my opinion - I have a very good friend who is a professional Air Force electrician. Part of his duties was to run the battery bay at a major front-line RAF station. The RAF used to have a contract with Exide to supply batteries, which was terminated early due to repeated failures, and even explosions of Exide batteries. Not the kinda thing you want in your fighter jet when flying over hostile territory, nor ideal in your Land Rover or Mastiff. He showed me some pics of failed Exide batteries, and also showed me the damage caused when one exploded and set fire to the battery bay.
Still think they have a "good reputation"?
I also did a battery drain test last night with a multi meter... left the car for 2 hours and tested... the car isn;t going to sleep. There were very big drains on a few of the fuses so this is actually the cause.
How are you doing the battery drain testing? Are you locking the car, leaving it for two-or-so hours, then unlocking it again? If so, the moment you unlock the car, you 'wake up' a whole plethora of modules, and this could give you false positives.
Are you aware of the bonnet catch trick? You need to leave the bonnet open, but trick the locking mechanism, and therefore the alarm microswitch - in thinking the bonnet is actually closed. Use a screwdriver in the lock to close the bonnet lock on the slam panel - if you have highline, use that to check you have done it correctly. Then lock the car, leave it for more than two hours, and then do your drain tests WITHOUT unlocking the car.
It would also be a good idea to turn off the TIM settings on your head unit, disable the interior monitoring sensor (button on the inside of the drivers B pillar), turn your headlight switch to zero, and move the wiper stalk to off. These should all minimise the basic 'wake up' devices, and hopefully help you narrow down other culprits.
The battery may be incorrect and will need to be changed but when you say change your battery and all the problems will be solved, that is actually incorrect.
OK - that was slightly tongue-in-cheek! But the lower spec battery is certainly not helping your cause!
