A friend of mine is travelling SNN-LHR-DXB with EI and VS in the near future and booked the ticket through a third party travel website. She would be entitled to check-in one free bag under VS's baggage policy but would she have to pay the EI checked bag fee for the SNN-LHR/LHR-SNN flights? The whole ticket has one reservation number but EI and VS are not codeshare partners. Both EI and VS websites aren't clear on the arrangement here.
I appreciate any help!