Cerithium Oil is a fictional company. The name cerithium refers to a specific seashell, and is a veiled reference to the aggressive environmental issues caused by Shell Oil.
Higgins, Keeley and Nora discuss the money issue about Championship players being paid Premiership rates. In actuality, most clubs have a "Relegation Wage Drop Clause" preserving them from exactly this issue, and automatically dropping salaries by, say, 20%, in this situation. There is also a similar "Promotion Wage Increase Clause" for the opposite situation.
In season 1, episode 9, Ted tells Rebecca that there's little girl out there, reading the magazine article about her and dreaming of putting on a eggplant -colored pantsuit and running a football club. In this episode, Rebecca is wearing that same plum suit while she shows her goddaughter around, which may be a way--subconsciously or consciously--of her referring to Nora as one of those little girls for whom she wants to be a role model.
In S2Ep2 ("Lavender") Keeley notes that the fictitious sponsor, Dubai Air, specifically asked for Sam to be in their ad campaign. It's likely that the only reason Sam was chosen for the campaign is the fact he's Nigerian, which seems even more likely when Sam learns that Dubai Air is owned by the fictitious Cerithium Oil, who has wrecked environmental havoc on Nigeria, his home country.
At the news conference Ted invites a question from the correspondent Lloyd, to go all Pat Benatar on him, referring to the singer's 1980 Billboard Top 100 single "Hit Me With Your Best Shot."