How difficult is the pti course in the British army and would the army help to get in any other armed forceS

Hello Aidan,
The Physical Training Instructor Course is a very physically and mentally demanding course. You will be expected to pass all Army physical tests with a high standard, you will then be taught how to lead and teach PT lessons and you will also be taught about the human body. Throughout the duration of the course you will participate in physical tests as well as classroom based tests and you must pass all of these tests to progress to your Pass Off Parade.

With relation to your question "if the Army will help get you in any other Armed Forces" I would recommend that you have a long think about what route within the Armed Forces, whether that be the Army or another Branch. Doing so will allow you to plan your career without risking the need to transfer branches.