Hi Jason,
As per the following link:
Trusts and taxes Types of trust, any income held within the Bare Trust, your son would have the right to all of the capital and income of the Trust.
In terms of the rental income, in some cases it will be made clear that the legal owner is not the beneficial owner. The legal and beneficial ownership may be separated by a valid Declaration of Trust. Guidance may be found on Gov.uk and the conditions required.
Thank you.