Tough environment but really interesting
At a senior level there are a lot of challenges faced at Transport for London (TfL), but if you are the sort of person that thrives in that environment then you will not be bored.
There are a huge number of very talented people in TfL too; there's a lot to learn from the staff and the customers.
There are few restful days in SHE, it is full-on all of the time. Personal accountability is important, because mistakes could become public.