In reply to Martin Hore:
I'm now in the same situation. My trusty RX100 Mk I has just died, so am pretty sure after some research that I'm going for the MK III. £365 new, can live with the reduced zoom, but looking forward to the 24mm wider angle. I know all the settings and menus, love some of the useful features, can use my existing spare batteries. Another option was the Canon G7X II, but have decided on the Sony having read comparisons.
If I get another 7/8 years out of a new MK III as I did with my MK I, I'll be happy enough.
Let us know what you decide.
p.s. the touchscreen on the MK IV and later models is something I'm not keen on, so the MK III is the one for me.