Best place to start is the IR web site.
http://www.inlandrevenue.gov.uk
Having just performed the calc what you need to do is :-
Purchase price + stamp duty + other fees = total purchase price (the higher the better)
You then have to refer the IR
http://www.inlandrevenue.gov.uk/leaflets/cgt1.htm to get the indexation allowance for owing the property 14 years.
You multiply the Total purchase price by the indexation figure to get the true purchase value.
Then take the sale proceeds figure and subtract all fees which gives you the value chargable.
Subtract Purchase Value from Value Chargable to get the gain on which CGT is chargable.
You then have to apply Taper relief which will bring the figure down further.
That final figure is the amount you pay CGT on so if its £1,000 and you are a 40% rate taxpayer, you would need to pay £400.
The IR web site is surprisingly good and don't forget to charge everthing you can to minimise CGT payable.
An example is shown below.
Of course having lived in the property you are entitled to further relief which I did not qualify for so cannot comment.
CGT Calculations on sale of property
Purchase price £50,000
Stamp Duty £500
Soliciters fees £500
----------
£51,000
Indexation X 0.507
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£76,857
Sale Proceeds £120,000
Fees £2000
-----------
Value Chargeable £118,000
Purchase Value £76,857
------------
Gain £42,143
Taper Relief 85% £35,821
CGT chargeable on £35,821