Thank you all for the helpful replies.
I have had the car since March of 2012 I found the wrong engine number whilst changing spark plugs or the water pump or the AOS or changing the water expansion tank in 2014 and emailed and called my local Porsche dealer (as I had bought parts from them) but they didn't respond and seemed unhelpful. I have had a leaking RMS since I bought the car (it had a report from a Porsche dealer stating leaking RMS) or maybe it's the dreaded IMS bearing!? Did get it checked in 2012 but two specialists reckoned no noise at bearing... Only done 15k miles and it's on 114k now and have waited two years for clutch to go so I could get bearing + RMS seal done too. I was hoping a replaced engine might be a benefit thinking that Porsche might have put a dual bearing in as a matter of common sense but it seems probably not.
I will try contacting Porsche via their website to see if they can let me know more about the cars history but here in UK Porsche have a snobbish attitude to second hand/old Boxster owners who cannot afford over a £100+ an hour costs and who try and fix it themselves. I also think if an engine is swapped, changed or replaced you should have some record in the service book and the car documents updated...Did Porsche seriously swap engines and put no details of this in the service record?
The engine may have been swapped by an annoyed owner privately and the car sold on