F5S Scrambling FTA channel ???

My F5S works reasonably well apart from the 'odd' scramble glitch that I had always put down the line in the past...

However, when trying to watch a movie on the FTA Sony movies channel yesterday the channel came up with the $ symbol and 'Scrambled' and just froze, sometimes for up to a minute.

Then it would clear for 30 - 40 seconds before doing it all over again. Just the same on +1 hour.

ideas welcome...