Can you confirm that your wife lived in the property during her period of part ownership of it and if that period covered a period when the property was let please.
No, my wife never lived in the flat in the period of ownership.
Will you email me when you ultimately reply to me, so I do not have to wait now? I will be happy to credit you and pay you when I receive your final reply.
I'm afraid that your wife may not be entitled to any main residence relief or letting because the transfer into joint ownership occurred during a period when it was not your joint main residence. Take a look at the HMRC manual page CG64950 here. You will see it says that the property must have been your only or main residence at the date of the transfer for the ownership history of the transferee (your wife) to mirror that of the transferor (you). There is some argument in the tax world about your wife acquiring a beneficial ownership as opposed to a legal ownership over the period of time she lived in the property but you can expect HMRC to put up a fight if they look in detail at the declaration of any gain and the claiming of reliefs by your wife.
Each month of ownership can only be accounted for once. If you lived in the property from January 1995 until May 2001 that part of your share of the gain will be exempt from tax. You will also be entitled to exemption from CGT for your share of the gain covering the last 36 months of ownership of the property (April 2010 to April 2013). Letting relief will be available for the period May 2001 to April 2010 so long as it was let or available for letting when vacant.
I hope this helps but let me know if you have any further questions.