There are some simple rules to follow when claiming expenses for buy to let properties and investment property.
Expenses incurred in the acquisition of the property such as legal fees, survey fees, adviser fees, broker fees, mortgage fees, stamp duty, travel costs etc are capital expenses. These can only be offset against capital gains when you sell or give away the property.
Expenses incurred in refurbing the property for improvement are also capital expenses. These can only be offset against capital gains when you sell or give away the property.
Expenses incurred in repairing the property for habitation or general wear and tear that are not ‘upgrading’ the property are trade expenses. These can be offset against rental income and profits i.e. your yearly self assessment return.
You cannot offset losses or expenses in property against earned income taxes or shares income or capital gains taxes. You can only offset trade/business expenses and capital expenses against others in the same tax schedule.