I may to totally wrong about this but I understood that, in respect of Capital Gains tax, if one was selling a PPR that had been rented out for a portion of the time owner, the capital gains was calculated from the time the property was first rented until it ceased being rented, rather than from the time the property was first bought until it ceased being rented? I.e. I buy a house in 2002 for 100,000 and live in it as my PPR. In 2004, I move abroad and rent it out - it becomes an investment property liable for CGT and is now worth 200,000. I return in 2007, with my house now worth 300,000 and decide to sell. My liaibilty for CGT is based on the difference between the 2004 and the 2007 price i.e. 100 grand and not the 2002 and 2007 price i.e. 200 grand.
If this is the case, does Capital Gains loss not work the same way? I.e. house bought for 300 grand in 2007, rented out in 2010 when it is now worth 150 grand, sold in 2015 when it is still worth 150 grand (let's say for conjectures sake ...). individual now unable to carry forward capital gains loss as there was none for the time the property was an investment?