Thanks Jack. I think I'm going to go for one. Leaving aside the great 1080/4K codecs etc, as you mention the focus looks really, really great. I did look at the GX85 and have watched a few blogs etc where its been used. There's one adventure vlog by a Canadian - Chris Prouse which is beautifully put together and makes full use of the OIS (she uses a gimbal as well) but even with all that effort you can see the camera hunting for focus at times and the video can look a bit blown now and again. (And I need all the help I can get in the focus department!

). Also - I'm then moving into bigger housings, lenses, ports etc etc
Nemrod - I'm certainly no expert but you might be pushing into DSLR territory with that battery requirement. I've used an RX100II - that one had really decent battery life. I'd have thought that might be the one to look at if you want something small and can live without the focus and video features.