How to Delay re-Synchronisation on a TG582N

[#1]

Well it happened sooner than I expected.
Typical noise pulse occurred at 20:00, some initial sign on routerstats that the noise was increasing (noise margin decreasing), then web pages stopped loading. I waited a while but the router did not automatically reconnect. So I used the same script as before (the enable freeze-showtime script) and about 2 minutes later, the router resynced and a new ppp session was established. So freeze-showtime was a success.
The downsides appear to be that freeze-showtime has some side effects which seem minor but only time will tell. For instance, the router does not report that it has lost sync, only that it has lost ppp. Other similar effects seem to happen which confuse the innocent (me). Those effects fit into what I saw this afternoon when I could not be sure what had happened.
I like using the enable freeze-showtime command to resync the router as that means the router default configuration is the normal default one and the "strange" operation mode will only occur if I positively trigger it
So thank you to everyone for their support. I will continue to see how things go and come back if I discover any problems.
@npr If you want to know more - just ask. I'm not sure how much detail you want.

[#2]

Thanks for keeping us informed of the progress, it's a interesting find and I'll add that command to my web site -- now we know it works. 

[#3]

To stop the dsl connection from my TG582n, using telnet, I enter the command:
    xdsl config status=down
To restart I enter:
    xdsl config status=up
The Internet connection gets established when the dsl connection is running.

[#4]

It's best if you drop ppp before dropping sync. See my reply #5 for the commands.