If you hunt around the forums you can find MP Audio Render for 1.2.3 it will be burried in the MP Audio Render Development thread, or you can just upgrade to MP 1.3 Final. Basically if you video is 24fps but your display only does 25hz it will speed both the video and sound up to 25fps. Same for all the other fps/hz combinations. Setup Instructions are in the wiki link.
Your TV does 50hz, but it would pay to check if it can do 60hz, 24hz and 23.976hz. The best way to check is just to change the windows desktop resolution + hz, then use the info button on the tv remote to see if the tv reports the same hz.
And in answer to your question the best hz rate for 23.976fps material is 23.976hz + MP Audio Render to hold synch.
The 2nd best setup for 23.976fps material is 24hz/48hz with MP Audio Renderer Speed Up
The 3rd best setup for 23.976fps material is 25hz/50hz with MP Audio Renderer Speed Up
Wow, thanks so much everyone, working like a dream now!! Cant believe how long ive spent with a crappy mismatched framerate, everything is silky smooth now!