I almost got into legal trouble by them when I left. Their contract also said I couldn’t work within 15 miles around any of their head offices in the world or any of their clients. They had hundreds of clients.
So I left and I did apply to work for their clients and they told my employer that this was against my contract. The employer laughed and said this isn’t enforceable anywhere. However, when they passed it by their legal department they said that it isn’t worth a legal fight even though it’s easily winnable. Just asked me to wait a year.