Tyre wear and part number help

Hello,

I have a Octavia Mk II VRS 2.0 TDi DSG Estate Blackline version.  It has covered 147K miles all original parts, only ever had to service it.  Recently it has started wearing the inside shoulder of the front tyres terribly.  I have had the tracking done but it has made no difference .  I suspect it could be the front suspension arm bushes.  Does this seem likely, how do I tell?   

Also,  have tried looking at changing the arms as a whole, or fitting power flex bushes.  But, there are a number of different part numbers available and none seem to match my VIN number which the relevant part (I think is) 8D250. 

Can any one please help?  I have tried ringing Eurocarparts but they were rude, useless, and gave me a part number for completely the wrong thing.

Cheers

Mark