Intermittant Picture and Sound Loss

[swilko]

Not sure if this is the right area to post as a newbie but here goes.
Started noticing over the last couple of months how certain programmes are breaking up on sound and colour. Basically the picture will go black and white and flash off and on, sound goes off, and this happens for a couple of seconds and then it is fine again.
The problem only seems to happen mainly on bbc channels, i.e 1 and 3 we watch a lot at cbeebies for me little lad, but it is starting to happen more and more now, (especially when strictly come dancin is on so the missus is giving me real ear ache about it !)
I have recorded the same programme on my separate dvd recorder which has built in freeview, and there is no interruption at all to the programme - so it points to something with my sky + box.
Any suggestions ???
Many thanks

[NewsreadeR]

Moved to more appropriate forum, for greater exposure.