So the battery arrived, followed the advice and popped it on charge in the warehouse at work this morning to make sure it was full but was showing 13.5v out of the box, came down after I had eaten my lunch and it was fully charged so fitted it, all in took less than 10min including setting the clock and resetting the windows. The new battery was an exact match size wise and everything, level indicator, vent hole etc in exactly the same place even the red plastic cover on the positive terminal just clipped straight back onto the new battery.
Only slight issue I had was the a couple of the screws for the battery holder were pretty tight (almost seized) but then I'm pretty sure that's the original battery I took out so to be expected but they wouldn't budge with the screwdriver.... Non issue though really as the 10ml socket I had ready for the terminals fit them too so with a bit of persuasion they started moving.
Don't know what I was worried about this was much easier than the battery changes I did on my last 2 cars (Jag and Hyundai) although maybe the fact it was in the boot and not under the bonnet made it feel easier
