Thanks again…
Re sanitation of the IP address it’s the address of the LTE connection so I believe almost impossible to get to from outside to any device… (my reason for doing this as I’m too dumb to run a VPN on the raspberry pi running victrons software)) it’s also just a test setup so no access to anything 
I might give the change of IP a go, however I have all ips reserved for stuff on the home Lan and something like 40 devices, so may take a bit of time! I have recently done it too so it didn’t clash with my home to work VPN…
I also note a new beta Merlin with overhauled OpenVPN… so may try that too!
Steve