the issue you mention is called "ghosting" and the following article tells how to resolve it:
if the issue still persists after following the article i would take the mac to apple store or service provider to have it looked at.
...At the moment the image retention doesn't really bother me but is it likely to get worse as time goes on?
My Yearly warantee is nearly up so if it is likely to get worse I'd prefer to get it replaced now...
Since your original warranty is still in effect, you can still buy AppleCare if you want. And since the IR sounds less obnoxious to you than the Samsung tint, hedging your bets with AppleCare might make sense.
I assume you've already spent some time in this thread and know the pros and cons of getting a replacement. There appear to be at least three variations on the Retina display. Samsung, LG SJA1 and LG SJA2. Reading through that thread suggests that replacements tend to be Samsung rather than the newer LG but even with what's probably the longest thread in Apple Support Communities history, it's still likely a small sample, so I don't think there's a definitive answer on what replacements are used. I mention that because my SJA2 has shown no signs of IR at all and no tint either, so there might be hope.
Update: Just stumbled on this thread which, while not local, suggests that once a Samsung is installed, there appears to be no going back, at least not for now. Two more years of warranty might help.
Thanks for that info. This is very useful.
I do prefer the look of the LG screen over the Samsung. My friend has the same laptop but with the Samsung screen and it doesn't appear as bright as the LG. It also has that yellow tint on white backgrounds.
I would prefer the LG SJA2 but I doubt you can pick and choose your replacement.
Since Apple deemed it necessary to solder everything to one board the AppleCare does sound like a good bet.
I'm still a bit disgruntled at having to pay an additional fee for what is an already overpriced machine. It's a shame Apple's warrantee doesn't extend beyond 1 year but I guess they don't have much faith in their own product lifespan.