My final payslip (Nov 2011)
Presumably you mean 2010
From this I calculate I have overpaid Tax by around 2k, but total NIC by about £12k!!
The tax sounds approximately correct (depends on the deductability of the pension payments)
I have no idea where you got the 12k NI rebate calculation from
employees/ers NIC isn't anything to do with your tax return - it is deducted by employers as appropriate and will normally be correct unless you have multi employments during the year or if you you were a director and they didn't register this fact on your payroll record.
Basically the 14k employers NI is simply a tax payable by your employer - you will not have had this amount deducted from your gross salary (unless there has been a serious error made.) - this amount is not really relevant to your tax affairs at all.
Pension - £1430
You will need to check to see what kind of pension payments you have made to decide if they go on the tax return.
If they are paid direct by you or are deducted from your net pay then there will be grossed up and included on the tax return - the amount paid into the pension scheme will have the 205 tax relief included at source.
If payments are deducted from gross pay by employer thereby reducing "taxable pay" then you have already had the benefit of the tax relief so the payments will not be included on your tax return.