We, and I see after reading the Sky Community Forum, many other people, are having problems watching recorded programmes on tv. The tv picture is fine but anything recorded is breaking and stopping, both picture and sound. There have been various suggestions, and these have been carried out on the Skybox, but although it is fine when switched back on, it only seems to last an hour or so before the problem is back again. Sky Helpline seems to want people to upgrade at more cost, but since so many people are having the problem, I think the fault lies with Sky.
We had a problem where all,series record programmes were disappearing before they were recorded. I solved it by unplugging the box for a few mins and plugging it back in whereupon it installed an update.
Fact 1:
Your Sky box uses separate feeds from the LNBs inside the dish for 'live' and 'recorded' programs.
Fact 2:
Your recordings are showing classic signs of insufficient signal strength.
Putting 1 & 2 together strongly suggests that there's a physical problem between the 'recording' LNB and the box, such as a cable not being properly plugged in somewhere. Check any connections you can access yourself (such as the one into the box) carefully. Then demand that an engineer is sent out to fix the problem.
Sky have admitted that the fault lies in their end, and that they are trying to fix the problem. However, it is taking lots of time. Lots of people have been talked into upgrading when it probably was not necessary. The Sky Forum is buzzing with lots of talk about it.