As others have said any decent company can default the codes and don't know what they are doing if they can't, they cannot be servicing it properly if they don't have the engineer code.
The local company should be able to default the panel codes and reprogrammed it without the need for ADTs engineer code.
Thinking about it tho they don't need ADTs code to repgoram fobs that's done on the master manager level not engineers.
Last time I handed notice in, it was a months notice I had to give.
Handed it notice at 0830 Monday morning, was sent to a booked PMV and by the time I got back to the office I was told to go home.
Heard similar stories over the years so wouldn't worry too much about it.
Have you tried putting the DVR in this DMZ? Or using a lower port?
I've done many sky routers and never had an issue getting into then or setting up ports or using dmz(I know DMZ isn't the most secure way or doing it)
What sky router is it?
What analogue bit?
Some of the dahua DVRs are a full tribrid (fitted them myself) and they will take HDCVI & Analoguge cameras & up to a certain amount of IP cams.
Plug and play as well, the DVR will automatically sense the resolution of the input and display the image from the camera.
I've fitted a few HIK systems and haven't had any callbacks with faults.
For now I wouldn't bother with IP and would go HD-CVI, still 1080p images and the price is usually cheaper than IP.
What are the extra restrictions of CVI over TVI?
As far as I can see CVI give greater cable runs, also offers recording in 1080p can be run on cat 5 or rg59
SDI seems like the one with more issues (from experiance) than CVI. Although I have not use TVI.
As above id say Either have a local Telecoms engineer sort the sockets out
And switch from ADT to a local-Taking over an ADT system shouldn't be an issue for most locals.
Check SSAIB or NSI for a local company
Is the system monitored via the telephone line or are they just using the phone line for Remote Servicing ?
Its probably not £1k for a new control unit but it depends on what you've got installed already.
The loop back stops the customer from using the dynamic DNS we setup when they are on their own WiFi
So they end up having 2 sites in the app for the same place
1-local (when on same WiFi as the dvr)
2-remote (everywhere else)
So use the customers router. Had a few issues with Homehubs but nothing major recently same with the technicolour ones I've done quite a few now no issues.