Thank you for a great, clear guide. Great kit from iFixit too including tools and new battery.

The only tricky part was getting the back off. Ditched the iOpener and used a hairdryer (left comment on that section). Once the back was off, took about 30 mins to dismantle, replace the battery and reassemble. Confirmed all working properly then used some B7000 glue to secure the back. Done and phone life extended another few years. Excellent.

Thanks for the above comments. I was also getting nowhere with the iOpener then used a hairdryer on the non-camera end until it was hot to the touch and managed to get a Stanley knife into the gap and lifted enough to get a pick in. Plain sailing from there with patient heating and working the picks in to cut the glue. Eventually success and the back came off.