Approach plates are free on the NATS website
NATS | AIS - Home
If you already have one of the Microsoft flight sims you can fly the airplane using the auto pilot functions just as you would on the rant sim. (I expect you can pick up fs 2000 for a tenner).
I've seen nothing here so far to convince me that there's any advantage in paying the extra cash for rant, and I also passed the IR skills test (FAA and CAA) first time.
I have rant 2000 but found fs2000 just as useful. I also downloaded an aircraft from one of the many flight sim websites for free with similar performance and the same panel layout as the test aircraft so it helped with the scan and cockpit familiarisation.
What does an approach cost these days ? You could probably get a couple in for 80 quid.