Hi there!
I did a placement in clinical health psychology just last year 🙂 In general, you'd probably be looking at assistant psychology or honourary assistant psychology roles, where you'll possibly have the opportunity to observe clinical work (ie., therapy work). In my experience, you'll be able to find these kind of roles in the NHS or in hospitals.
It might seem daunting, but I recommend researching hospitals local to you, checking to see if they have a psychology department, and emailing them to ask if there is an opportunity for a placement student. Some hospitals already put these up opportunities on the website - its just a matter of searching for it.
Hope that helps
~ Fatiha, Cardiff University Student Rep