Had this 28" w/screen for 3 months and paid £530. The convergence is not very good especially in top left corner. Retailer is taking in to workshop for a week but has said will probably not be able to make any better! "Most of these sets are like this", he said. Can anyone advise if I have grounds for a replacement (or newer model) if still not happy when they send back or am I expecting too much for my money?