Hi,
Income from property held jointly by married couples is treated as beneficially owned by the individuals in equal shares. Consequently, they are taxable on the income 50/50. This rule applies even if the individuals own the property in unequal shares . By completing a declaration via form 17 , this can be disapplied.
In your circumstances, the property is not jointly owned. Your wife should continue to report the rental income via her Self Assessment return as she has 100% beneficial interest.
You can find guidance on Capital Gains Tax here:
Report and pay your Capital Gains Tax
Thank you.