Well its not Junction17 trader so thats a good start however:
"Huge History file,Nissan Folder/Manuals/Receipts for work done" does not mean Full Service History unless stated. And theres no mention of any kind of warranty which is usually the main benefit for paying a premium for main dealer prices.
As ATTAKZ says, open the bonnet and check if you have dual air boxes, if not you're getting the facelift interior/exterior without the facelift engine essentially. Use all of the above to haggle the price down
that is the facelift with rev-up engine, price may be a little high but all depends on the condition and if it's been looked after.