Prince Harry could serve on the front line again

The speaker expresses disappointment about returning early from an assignment, reflecting on the experience and the desire to be with peers. They look forward to future opportunities, including training for an Apache helicopter, and express a strong ambition to return to Afghanistan when the chance arises.

What are the speaker's thoughts on the opportunity to return to Afghanistan?

What does the speaker mean by 'the appetite always that I've always wanted'?