Is this something that has spontaneously happened?
Or is it that you switched to NowTV Broadband, and your CCTV stopped working as a result of that?
CCTV usually requires port forwarding (which you may have had set up before) but is strictly off by default on NowTV Broadband, as having the router wide open to this would be a considerable security risk.
If this is what has happened, I suggest you get in touch with the CCTV providers, who should be familiar with this issue, and able to advise you of what to do to allow this with the absolute minimum security risk.
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