Lip Sync issue only on recorded programs

[Babba]

I've had a HD box since January and in the last two months suffered from horrendous problems with lip sync but only on recorded programmes. I do not have an audo amp, and the TV uses its HDMI for video and sound. In the past it seemed linked to fast foward/rewind use but now it happens from the start of each programme and I cannot get rid of it by the old trick of stop, back to planner and start again.

Anybody any ideas or will I have to try and get Sky to acknowledge there is a problem?

Apologies for the new post, actually got Search to work and saw some of the others. Gives me a few things to try.

[Kenedin]

Try 1080i as your HD Resolution Output, or if you don't fancy that, switch to a HD channel ( eg Sky 1 HD ) before playing back your recordings.

[Proppinupthebar]

Does it affect all channels or just HD ones?
What make of box?

[Babba]

Amstrad box. Yes only the HD channels.

[Proppinupthebar]

Does Kenedins suggestion of watching Sky One HD and then starting playing your recording work?

[Mr Spouse]

I find 143 BBC HD the best to switch to before playing back recordings on my Amstrad. I do it pretty much without thinking now!