You mean capital gains tax on the part of your home which was used "commercially"? That only applies if the part in question had been "exclusively" used for business.
Sticking a computer and a desk in a spare bedroom or dining room to use it as a home office does not count because the room can still be used for its original (domestic) purpose. Having something you call a home office is quite common with employed people.
It would be different if you had for example installed machinery or equipment to make that part of your house into a studio or workshop, If you then used it to make goods which you sold in the business then it could not conveniently be used for domestic purposes. It would have become a workshop or studio so it would be for "commercial" use.
Should women have equal pay and opportunities?
To think that London, or anywhere else for that matter, does not belong to any one demographic