Be realistic about... adverts for jobs
No, it's not from 'The TES', but the intention is the same: someone wants to seduce you. Schools are, of course, basically honest, but few can resist presenting themselves in the best possible light. Be wary, then, of any content that goes beyond telling you where the job is, what it will pay, and how to apply.
Go to the TES jobs section, and choose an ad at random. Pick your way carefully through the text, and sift out the facts. Ignore the adjectives and adverbs. You're left with a simple signal saying, 'There's a job here, please apply', and that's not informative enough to be the basis for a long-term commitment.
You need to know far more. Send for the information pack, which should contain, at the very least, a job specification, statistical information, and something about the department in which you might work. It might even tell you where your predecessor went and why.