Ship charter for charity ball in UK

Hi apologies if this is the wrong place to ask.

We have been tasked with producing a 25th anniversary event for a high profile charity in the UK. We would be interested in chartering a vessel to depart from Falmouth in the UK for a one night cruise 6pm-6am for approx 2000 persons. Accommodation isn’t essential but large open area that we could transform into an entertainment venue. We have approached cruise ship companies but I’m wondering if it was feasible to look at a different type of vessel a ferry where we could transform the decks into venues. We are an experienced event production company with zero maritime knowledge…budget available up to 100k

Thanks in advance