sony32fx68 / slvse730 weird problem - help !

I have a SLVSE730 video hooked up to a 32fx68 tv (via AV3).
The video also has a sky digibox into it's Av2.
It also has Analogue NTL cable via the RF.

I set the TV up using autosetup and it recognised the 10 NTL channels. It downloaded them to the Video when I added this. So far everything is great except ............

If I switch on the TV then the Video I loose channel 8 (sky one) on the TV next time I select it. I either get a black screen or a very very poor picture. Every other channel works perfect.

If I either switch the vcr off OR press the TV/VCR button on the VCR remote I get the channel back perfect on the TV.

It does not seem to matter which channel the VCR tuner is on.

Any ideas as I am completely lost ?