Hey hun u can put in a request for an early or first admission but it usually comes down to medical need/proceedure time in theatre. U have to have a chaperone when u leave hun. U dont have to have someone when u arrive.
I felt as high as a kite when I left and I was an overnight case. I passed out/collapsed when I got home felt really out of it. If ur taking the train make sure u book a seat and bring a pillow to rest on. I got a taxi home and was ok I had tons of layers on.
I always find if ur travelling from quite far usually helps to get the earliest appointment that way u give urself plenty of time to get there and congestion isn’t too bad. Plus should be more transport running if u miss ur first train or coach not long a wait for the next one
Just let ur pc know ur situation that ur travelling and I’m sure she’ll do what she can to assist.