Yup, he's an MP with representation of a whole constituency.
Some people even have 3 jobs!.
I look at the bunch is government now and i think how many of them want to even work to make the country better rather than working in government to get a cushy number. I guess Grayling is one to hate on a bit easier as he's one of johnsons chums exemplified by his stellar work to hand out a contract to a shipping company who didn't own any ships or even sailed a ship at all.
I've typed all this and having another think, i think the thing about this deal is, he's an "advisor" to the top port chiefs. If he was doing what Boris did and writing opinion columns in the newspaper i think it'd be less of an issue as at least i know he's being employed to debate his views. IMO I don't see Grayling doing on any advising, he's being paid purely because he has influence on enough people to arrange more special contracts/rules for the likes of these port companies.