Zero chance of the iFixIt suction cup sticking to the battery as it is too big so hangs over the side and doesn't get a seal.

I used loads of IPA, waited, tilted phone about, more IPA, more tilting, more IPA and prised the battery a bit at the bottom with a spudger, more IPA, prised a bit more at the bottom then (gently) prised it from the top left and it came out.

Thought I'd done something wrong here as there wasn't a cable attached to the back - the fingerprint reader hadn't come away with the back, but had stayed with the phone.

There seems to be a lot of glue at the bottom, I broke the glass as I was cutting past the charging port - not sure if it was already fractured or just not enough heat (I used Sellotape so it didn't break up into pieces!)

I think LOTS of heat & patience is the key!

Be very careful around the corners and bottom (probably top too, but I didn't have a problem there). Make sure you've cut in far enough down the side first (go in about 1cm) but less round the corners and work in slowly.

Be careful not to tear it as it comes off - especially the side bits that stick out a bit

On my phone the fingerprint sensor did not come off with the back cover but stayed on the phone!

Angle the pick up very slightly so the point goes up into the curve of the glass, not down towards the workings of the phone