Panasonic DVD sound problem

Hi
Ok I have a Panasonic DMR- EX75 hard disc recorder with free view tuner connected with scart lead to Philips Digital Tv with free view tuner also Rf cables connected. Until recently there as been no problems when playing back recordings, but what is happening now is that im getting the sound from the recorder and also the sound in the background from the station set on the Dvd recoreder as well. Only way I can stop this is to unplug the R/F in to the DVD or to set it to a channel with no reception. This I cant do if im wanting to record and play at the same time. Ive checked the scart lead is connected ok (wouldnt have a picture if it wasnt) its now connected Ext 1 to Ext 1 as Ext to EXT 2 seemed worse also tried other combinationsbut none eliminate it. Any Help appreciated.

                                   Peter