I fitted a new battery to mine yesterday.
Wasn't quite as easy as I'd hoped as getting at some of the bits can be quite fiddly - would have helped if I had some smaller rachets (or just more tools generally).
Also, the battery I bought was a good inch / inch and a half longer than the old renault one which made refitting a bit more difficult too!
I ended up having to remove the airbox to give sufficient room to easily remove the old battery.
all in all, didn't take that long and wasn't difficult, just took a bit longer than expected!