:whattheysaid:
You were offered the promotion on merit. Every employer employs knowing their legal obligations around leave etc, and the offer was made by them with that understanding.

One of the key tasks for a TL is to develop team members to their full potential. So you'll have a year to train your team, and develop someone you can trust to manage the team while you're away. Plus your pay while you're on Mat Leave will be higher, which gives you more options.

So congrats on the new job!