CGT question, help needed!

scottpattison1974

HI I am looking at the following question.
Christine made the following disposals in the tax year.
She gave her sister an antique necklace that she had bought for £5000. The necklace was valued at £8000 at time of the gift.
She sold her Jaguar E type car for £18000. She bought the car for £6000, and spent £10000 having it professionally restored.
On the 31/12/2019 she sold her house in Dorking for £470000. The house had been bought for £80000 on 1/1/92. Her use of the house was as follows:
* 1/1/92 - 31/12/01 Occupied as Christine's PPR
* 1/1/02 - 31/12/03 Rented out as Christine went on a world holiday. (Lucky!)
* 1/1/04 - 31/12/02 Occupied as Christine's PPR
* 1/1/13 - 31/12/19 Rented out as Christine moved to a new PPR
Christine's taxable income is £30000.
Required
Calculate the total taxable gains for Christine for the tax year.

Now the actual answer is as follows (In the back of the book (Osborne tutorial Personal Tax))
Necklace £
Deemed proceeds (Market Value) 8000
Less Cost (5000)
Gain 3000

Car is exempt.

House.
World holiday period counts as deemed occupation under the 'absence for any reason' rule since it is for less that 3 years and is between periods of actual occupation.
1.5 years of the final seven years counts as deemed occupation since it was a PPR before this. The house is therefore exempt for 22.5 years of the 28 years of ownership, and chargeable for 5.5 years.

Right I understand the calculations for the Necklace and I know that the Car is exempt. It is the Property that I cannot get my head round. Could anyone explain step by step the calculation for the property and what periods are classed as what?

TIA

Scott