Overall, from my experience the past years since exiting a Sussex, Job hunting was literally a pointless endeavor for 24 months, all big corporate companies exist primarily in London and have a undisclosed biases of recruiting from the top 10 Russel group units, plus there are way to many candidates from these 10 unis for even them to choose from. A good rule of thumb is to look at the companies linkedin and scan their employees profile, u will see a very obvious pattern of which school they hire from, and believe it, i never see Sussex.
If u go to Sussex as Undergrad, get ready to work ur ass off to get into a top 10 Russel group uni for Masters, then only then u will have a chance to compete with people already seen as a higher caliber as you. Good luck, that's the only way.