The USA has very standardized training doctoral curricula that are codified into licensing laws. The UK and Australian programs will not meet these requirements.
Keep in mind that clinical psychology in the UK is a master's level profession. It is likely that this is true for Australia.
Pragmatically, the plan to complete a foreign education does not seem to work. If one searches for a USA based licensed psychologist with a DClinPsych, one will find almost zero results. When that search is further limited to individuals who have obtained their license in the last 10 years, the results are even closer to zero. If you exclude visiting professors with significant academic ties, it's even lower.
There is a reason for this. A quick review of Manchester's program shows it is a 3 year program to graduate. Now compare to a median program in clinical psych with 4-5 years of training, and 1 year of formal internship BEFORE graduating. After graduating US psychologists still have to complete 1-2 years of post doc in order to get licensed. That's a difference of 2-3 years, before post doc.
For this plan to work you'd need: ensure you are eligible for graduate charter designation with BPS, complete a DClinPsych, convince APPIC to allow you to apply for match (unlikely), fly to the USA multiple times for interview, best other students with a completely normal education and grading system in that highly competitive application process, complete a year long full time internship, convince ASPPB that your program is equivalent to a US program, convince ASPPB that your clinical supervision was equivalent to a USA program (it's not), then complete the EPPP, pass the test, convince someone to take you as a post doc which would again require you to explain why the educational differences are not a liability and how your foreign education meets their specific state requirements (e.g., some states require APA curricula or equivalent, some states require specific course titles), then convince the state board to accept the educational differences (unlikely, as the applications are judged by a low level bureaucrat who has zero liability in saying "no" but a high level of liability in saying "yes"), then potentially complete an oral examination where all of the above would again come up. If you apply for states with other specific requirements, you would likely have to complete additional coursework before you get licensed (e.g., Oregon, California, New York, etc).