Screen judder and lip sync issues with LG

I have an LG 42lx6900 which I bought a couple of months ago via Richer Sounds. The image is OK (very good on blueray) but two issues are increasingly blighting my enjoyment. First, screen judder when images are moving fast across the screen in either direction. From what I can find online, this is a processing issue with many screens, but why should we accept that? My previous ancient Toshiba plasma never suffered it. Can anything be done and are other TVs better? 

Second issue is the sound and image are only sometimes out of sync. I'm using the inbuilt freeview and playing through the inbuilt speakers. The aerial come to the TV via a PVR which is usually switched off, so is effectively just a junction box. I've spent the morning online using LG's help line and have just rebooted the TV with a different level of firmware than was on the TV, but I seriously doubt it will make much difference (as per other forum threads I've read). Can anyone suggest other solutions? If I'm in a weak reception area, might that effect it? Why does it happen on certain TV channels and not on others? 

I find the whole experience extremely disappointing. Help! Has the magazine ever covered these issues in detail and, if not, why not? Should it make more of an issue about it, if mine is not a unique case (as I'm sure it isn't).