Hi and and Welcome
A white M reg carb mini I hear you say? Does the Log Book by any chance say Mini 35?
The Mini 35 limited edition came in three colours, Arizona Blue, Nevada Pearlescent Red and Diamond White. It had a Purple and Grey interior (Not attractive lol) If it is a LE and you wan't rid of the Limited edition stuff let me know I'm after a badge for mine :)
It's a Sprint not an LE.
Take it you mean Sprite not Sprint? A sprint has a few inches saved off it's body and is quite rare, the link below shows the difference in height to a standard mini.
http://www.google.co.uk/imgres?q=mini+sprint&hl=en&sa=X&tbo=d&biw=1366&bih=667&tbm=isch&tbnid=-5Ys3v_YzWDk8M:&imgrefurl=http://www.statim.co.uk/Minisprint.htm&docid=QiRSMQ7-miqFwM&imgurl=http://www.statim.co.uk/images/MiniSprint%252520comparison-e.jpg&w=1028&h=502&ei=aWG1UMvaPMWL0AXZioH4BQ&zoom=1&iact=hc&vpx=4&vpy=206&dur=1189&hovh=157&hovw=321&tx=218&ty=83&sig=109961060860699864544&page=1&tbnh=139&tbnw=278&start=0&ndsp=18&ved=1t:429,r:0,s:0,i:99
With regards to price, we really need more detail than what you have given, people are jumping the gun here. But for £2,500.00 you can get a nice clean mini with that in the current market. But really it comes down to rust, will it be needing a welder on it anytime soon? Key places are under the headlights, A-panels, bottoms of the doors, the cills, around the gutter and around the scuttle close to the windscreen. For the money you would expect very minor surface rust but nothing to cause any problems anytime soon when it comes to MOT time.
It seems to have a few nice toys on it which is good but if the body isn't sound it could potentially cost you a lot more than what it could costed to buy the toys to put on a rust free mini!
Just don't get carried away with the gadgets and inspect the body and you should be fine.
Welcome to the forum!
Chris