Property held jointly by married couples or civil partners: Form 17 rule: declaration is optional
A couple do not have to opt for a different split. A couple could accept the standard 50/50 split for jointly held property, even if one spouse or civil partner holds 90% of the capital and income and the other spouse or civil partner holds 10%.
A couple can make a different choice for each asset. In some cases they can choose to be taxed on their actual entitlement; in others they can accept the standard 50/50 basis.
The couple do not have to make a declaration as soon as they get a new asset.