Hi Rich Lad,
Regarding the split of expenses, please see guidance available at
PIM1030 - Introduction: jointly owned property & partnerships which advises the following- However,
where the joint owners are husband and wife, or civil partners, profits and losses are treated as arising to them in equal shares unless:
• both entitlement to the income and the property are in unequal shares, and
• both spouses, or civil partners, must inform HMRC that their share of profits and losses is to match the share each holds in the property.
Therefore, the share of expenses would match your wife’s share in the property.
There is no guidance to indicate the bills for the property business must be in your wife’s name.
Please see guidance-
Work out your rental income when you let property Capital expenditure and
PIM2030 - Deductions: repairs: is it capital? the expenses must not
be capital in nature if you wish to claim them as an expense.
Examples of how to work out Income Tax when you rent out a propertys has good examples of maintenance and repair costs too.
Thank you.