Hi Abigail,
It is great that you are interested in studying Psychology with the Open University. The choice is yours, if you want to register for the Honours degree or the Diploma of Higher Education. The Diploma is the first two-thirds of the Honours degree.
If your study is for a career I recommend doing some careers research and getting advice. A good starting point, with some useful links, is this page from our Help Centre:
https://help.open.ac.uk/how-do-i-become-a
There is also some information here:
https://www.open.ac.uk/courses/careers/psychology
Generally, each 60-credit module will require 16-20 hours per week of study. It is important to consider how you will fit study in with your other commitments such as work, family, social, etc. Our Time Planner can help:
http://www.open.ac.uk/courses/do-it/finding-time
The next available start date is in February 2022, with the deadline to register being 13 January. If you want to discuss your options, or to register, you can give our friendly advisors a call on 0300 303 5303, Monday to Friday, 8:00-17:30.
Our full contact details can be found here - https://help.open.ac.uk/contact/