Business ADSL port 80/CCTV

[#1]

I've got a plusnet line (21.8 down/2.4 up - annex M) which we use as a second adsl feed to monitor our site's CCTV system.
2 days ago, it stopped being able to be connected too (port 80 for the primary connection, 2 higher ports for data).
Today I moved the primary port to 1080, and everything connected.
I've checked the firewall settings for the account on the plusnet account and it is turned off.
I can't find any changes at the site end.
Anyone else seen this?

[#2]

Hi ChloeRed, welcome to the forums.
We do not perform any other port blocking than that implemented in the broadband firewall. I can see this is indeed off (and it is a status that we know means it's not a recent change that may simply be pending on your connection) so not an issue here.
What router are you using with the service?

[#3]

Router is a Vigor 2820n.
Everything was fine till Monday, and at the moment I can't find anything wrong on the router.
I'll keep looking.

[#4]

Have you been able to install the Vigor tools at all?
The syslog functions of the router are very good and should be able to log what is happening either at firewall and NAT/PAT level to see what is happening.

[#5]

No, because the only device connected to the router on site is a CCTV DVR.
I will look into it further when I am on site.