Arriva training bond

Just wondering if anyone has been chased by arriva for their training bond? I’m leaving after 9 months. I’ve heard a few things.

1. they’ll take a week in hand off of me when I leave (which I’m lead to believe they can’t do anyways) and not do anything else since the cost of legal fees isn’t worth the work

2. they chase 1 in 5 people as a formality

3. they’ll sell the debt and the debt collectors will send me a letter which some say to ignore?

Thanks