Well when I was doing it and we required someone to be in for surgery at silly o'clock the following day who lived quite far away then we would book a hotel for them if needed, usually at the St Giles (link that didn't work but just google St Giles on Tottenham Court Road). If they were coming in for an overnight stay then we'd only pay for the patient but if they were coming in for day surgery then we'd have to book a double room as day surgery won't let you leave unless you have someone to collect you.
I'm relatively sure it hasn't changed so give the PA a call tomorrow. I've left a message for her and will let you know if she gets back to me before I go to bed.