When I was in London last June, I'd mailed off applications ahead of time to the casinos I'd planned on visiting. I never heard back from any of them. When I arrived in some cases they seemed to have my name on file. At other places they didn't seem to be able to find any record of me but seemed to take my word that I'd mailed in an application and gave me the membership. I was not turned away or forced to wait 24 hours at any of them. Note I was going to places with free memberships, not the fancy places.