Kesme and Soba, a married couple, require advice on the capital gain on a future sale of the family home

Rental income in respect of furnished rooms in the family home:
– Kesme and Soba purchased the family home on 1 July 1990 and have lived there since that date.
– Three furnished rooms have been rented out to an individual tenant since 6 April 2013.
– The tenant does not share Kesme and Soba’s living accommodation or take meals with them.
– The three rooms represent 30% of the property.
– The annual rent is £14,400 and there are allowable expenses of £1,600 per year.

Required:
(b) Explain the effect of renting out the furnished rooms on the amount of the taxable capital gain on a future sale of the family home. (6 marks)