"Even more to the south" is good. You can also say "Further south." Хорошая работа!

Спасибо, Алексей)

Usually it's just the "south" or less often it's "southerly" . Here are three examples from context,reverso,net 1)Мы нашли его в 5 километрах южнее. We found him three and a half miles south. 2) Мармольское ущелье расположено в горном массиве в 17 километрах южнее города Мазари-Шариф. The Marmoul gorge is located in a mountain range 17 kilometers south of the city of Mazar-i-Sharif. 3)Пересёк побережье, направился южнее на 12 градусов, что означает... Flew out over the coast, banked southerly 12 degrees, which - which means...