There may be problems we still need to tease out, but we will leave no stone unturned in our bid to make London the host city.

Meaning of the quote

This quote means that even though there may be some challenges or issues that need to be carefully examined, the British politician Sebastian Coe and his team are going to work very hard and do everything they can to try to make London the city that hosts an important event. They are determined to explore every possible option and leave no part of the process untouched in their effort to achieve this goal.