Do you see a scart socket labeled AV2 Decoder/external (Normaly the bottom one but actualy the top one on your model)
thats were the scart leed needs to go from the sky plus box.
If you are watching the DVD then you don't need to watch SKY and the sky plus will record as normal. when you turn the DVD off, the SKY plus feed will be switched over instead so you can watch SKY plus.
Now this set up allows lots of options for backing up what is on the sky HDD
Via the philips DVD R you select AV2/ext2 then you play back the film/Tv show you want to burn to DVD or watch on the SKY box.
Now you can record it on a DVDR If there is not copy protection on the Film/tv....this will then allow you to watch the DVD back up on any DVD player and not just the limited to the version on the SKY plus box TV.
Now you can erase the film/Tv from the sky plus and have more room for more Films/Tv.
The problem with this is you end up with bucket loads of DVDR in your HOME and spend more time cataloging the DVDr then watching SKY.