Property Manager

We are managing a property on behalf of an individual Landlord/owner. Usually we would only pay the legal owner of the property / Landlord, but in this instance the Landlord has requested we split the income in line with a Declaration of Trust they have provided (which has been executed as a deed). The declaration splits the rental income between him and his wife as Tenants in Common on a 99:1 split in favour of this wife (who is a beneficiary but not an owner of the property). The declaration further states that the onus on keeping the property in repair is solely the responsibility of the owner and not the beneficiary. The Landlord lives overseas and is registered with the NRL scheme and therefore we have to submit the statutory notice return to HMRC. The beneficiary is a UK resident. In this instance, is the onus on us as a Letting Agent to distribute the income / expenditure and pay the beneficiary, or is the onus on the owner to distribute the income accordingly?