regent and ritz carlton arent much more, at about €200
(ritz carlton has amex plat 4th nt free through aug 31)

unless negotiating with hotel, possibly via virtuoso agent, need amex plat for guaranteed 4pm checkout

if OP has amex plat or is open to above, they could get more info in this forum, including re agents
as TRAVELSIG points out, chain hotels are often overpriced and poor value, vs lux/boutique/independent
just need more info from OP