I got the e44 from tanyabatteries. Very fast delivery and local shops by me couldnt even get close to thier prices.
Can I just second this. Got mine from them last week. They supplied the E44 for LESS than local suppliers wanted for inferior batteries.
A few tips if you are changing your battery:
Before you change the battery, park straight with the steering wheel dead ahead.
The E44 is larger than the stock battery but will require a little bit of shuffling to get it into the correct position. Remember your battery box will actually come apart so take advantage of that. Once I realised that life became much easier! When done just clip it back together.
When you turn back on the car will start *****ing about faults. Let it settle down for 30 seconds or so then take it for a drive. Everything will clear.
The one touch window closing & opening will have stopped working. Open each window all the way, and then close it again. You may need to do this a few times. One touch will now work. NB my passenger window remained stubborn but the next time I cycled the ignition I programmed it first time. Some people report it can take a few ignition cycles to work.
And the car will forget what the time was but not the date! Bizarre!
Finally, please properly dispose of your old battery by taking it to a council dump. I saw some idiot had dumped one in a local lay-by a few weeks back. May a pox fall on their household.