Isnt there an allowance if you lived in the property for a long time???
Hi You get credit for the time you lived there known as private residence relief - and this also covers the last 36 months of ownership (due to change to last 18 months from 06/04/2014) and also will qualify for private lettings relief, as this was your main home AND you have let it out to tenants (and I assume declared all rental income to HMRC) but a capital gain will still arise.
You only lived here for 4 years (from the date of ownership to when you moved out) and then have the period from Jan 2006 to when you sell, which is 8 years when it was NOT your main residence!!!
And whilst 3/1.5 years taken off these 8 years for private residence relief, and any remaining gain can be reduced by the private lettings relief, and the first £10,900 of any gain is exempt (this is to increase to £11,100 from 06/04/2014) you are still likely to have a capital gain to consider.