Conrad has always been very accomodating when they can. I got 9pm check out earlier this month, but that was mainly down to the fact that one of the lounge staff members I know the best was working when I requested it and she sorted it. I got 8pm from her last month as well.

They are generally very good with 4-6pm checkouts for Diamonds when they can.

Occupancy levels are fluctuating a lot at the moment so if it's low at the time you should be ok.