Sound problem

[qanda]This thread is about the Panasonic DMR-EX77. Click here to see full specs[/qanda]Ok Here goes hoping somebody as some ideas here or has experinced this problem . Firstly its the Panasonic DMR EX 75 and not the 77 but that wsnt in the drop down box.
Here is the problem and this as only happened the last few months so things must have been wired up ok at first.
I have a freeview Philips Tv with Tuner connected with RF cables to the panasonic DVD HD recorder and the connected together with a scart lead. All was well with this set up.
If I record a channel say BBC 1 for those english amongst us the channel changes to 1 in the DVD windows and records the program.
I then PLayback the program It automatically switches to Ext 1 Or 2 Whichever its connected to 2 Ext in this case and plays back the recording.
However what i then have is the sound of the Playback and also the sound of whatever is being broadcast at the same time on the channel which is on the DVD at that time,
So if im recording and playing back at the same time I have the Sound from Both at once.
This Is driving me crazy Ive Phoned Philips and they say its the DVD and ive phoned Panasonic and they say its the TV.
All I know is i wouldnt ever buy any of their crappy products again as the Customer Service is the worst Ever.
Any genius out there PLease Help

Peter