OK so I can capture with HDV Split and the clips play back perfectly in synch - I can capture and edit in Windows movie maker for gods sake and it's in synch - but as soon as I import HDV clips into Premiere or capture new footage - out of synch

I have a new, purpose built fast rig for editing with CS5.5 and this is costing me money as I have to re-synch every clip

Sure bring out CS6 when windows movie maker performs better lol!!!

I'm pretty angry though

Is it out of sync if you use HDsplit to capture the footage and then import into Premiere? I thought the problem was only if you use Premiere to capture the footage?

First question: have you let PPro finish conforming all of the the audio before you start trying to play back the imported HDVSplit file? If not, try doing that and check if that helps with the problem.

Second question: have you called or e-mailed Adobe help? (My experience is that they are usually responsive but slow; maybe you've tried this and not been helped?)

Third, have you checked the system audio drivers as Paul suggested in the other thread. Concurrently, have you checked the audio hardware settings under Preferences in PPro? Do you have choices there? What happens if you change the hardware choices.

Fourth, have you cleaned the media cache?

Fifth, have you gone into the project settings and set your scratch disks for some place other than C:\Users\etc. Specifically, are your scratch disks on one of your 7200 RPM media drives rather than the C: drive?

Finally, do you have some sharp point in the sound track that you can compare to the video as Paul suggested? This would tell you pretty quickly is the audio is being processed incorrectly (your audio peaks are off from where they should be) or if it is a playback issue.