OK - Steps taken so far:-
Range of IP addresses in router changed from 2 to 100
IP address in CCTV changed to 198.168.000.200
Alternate DNS changed to 198.168.000.002
Created 2 services in in router
cctv TCP 80..80
cctv2 TCP 6036..6036
Added 2 Firewall rules in Inbound services which now read :-
......No...Enabled..Service Name..Action.....LAN Users........................ WAN Users..........Log
......1........Y..........CCTV .............Allow.......192.168.0.1 (80:80)........0.0.0.0..............Never
.................................................Always.........................................(1.65535)
......No...Enabled..Service Name..Action.....LAN Users......................... WAN Users..........Log
......2........Y..........CCTV2...........Allow......192.168.0.1(6036:6036)......0.0.0.0..............Never
................................................Always............................................(1.65535)

CCTV Config now reads:-
HTTP Port 80
Server Port 6036
IP Address 192.168.0.200
SubNet Mask 255 255 255 0
Gateway 192.168.001.001 (Please note 001 in 3rd Group - ????)
Preferred DNS Server 192.168.000.001
Alternate DNS Server 192.168.000.002
PPPoE not enabled.
(Yes CCTV does show leading zeroes)

Still works fine on wifi on Ipad and Smartphone.

Tried using 2 different apps on Smartphone Meye and SuperLivePro with Wifi off and Mobile Network on (data enabled and mobile data always on) - still doesn't work.
Setup requires me to allocate a device, give the service a name, enter Public IP Address, Port No. User, Password.
I take the last two to be the User Id and password of the CCTV.
I have tried Port 80 and Port 6036 - both with no joy.

13.59 - I have just tried a port tester on 80 and 6036 - both show as closed

Really appreciating your help
What have I got wrong

Edited by deleted (Sun 11-Nov-18 14:00:35)

In the CCTV why is gateway not set to 192.168.0.1?

No idea unless I've changed it by mistake at some stage - off to take the dog for a walk - will change it when I get back and report back.

Gateway changed to 192.168.000.001
Still the same result
"Failed to connect to device.Please check network and device"

Still works OK locally on wifi

Don't know if this is relevant or not but in the router under Maintenance/Attached Devices the CCTV is not shown

If firewall rules means port forwarding then the 192.168.0.1 is wrong, you need to put in the IP address of the CCTV server i.e 192.168.0.200

I'm in

Can't thank you both enough - I owe you a pint or 3 if you're ever in Malvern

Now for the security side - I'll set the password to the CCTV to a really secure password.

I know the public IP will change periodically so to some extent I guess I'm protected there ?

Is there anything else I need to do ?