Zero evidence of this. This year, it felt like you were never out of sight of Sleep Token merch. Their fans will show up because they’re already at Download. The majority of Sleep Token fans are heavy music fans whose are far more likely to like bands like BMTH, Architects, Bad Omens and Spiritbox.
"Overlooking the sea" sounds like the location is the same as last two years (Amazon stage). Plus I don't think they're putting together completely new stage, bars, toilets etc. just for Sunday.