For the interview, I imagine that you'll essentially need to convince the hirer that you're a surer bet than a random NIE trainee they'll request should they not take existing teachers to fill the vacancy, which I'd say is a pretty low bar to beat.

However, you'll also be competing against other applicants - no real way to predict how tough that'll be. Guess it'll be harder if it's a popular school (for whatever reason).

All the best!