We have an RX100 M5 for sale hardly used. Been in the water around half a dozen times. The reason for sale is that it is not being used as I am using my Nikon DSLR instead.
I am based in the UK near Portsmouth.
The RX100 M5 was purchased new from Bristol cameras see receipt.
The Nauticam RX100 M5 housing was purchased 2nd hand but was hardly used if at all.
It also comes with an external charger and 4 batteries.