I had a bad experience trying to do this on my most recent visit. We made a PS for 7:50pm, and stopped by that afternoon to request an outdoor table. I was told that they can't guarantee outdoor tables, but they would try (which I knew already). We arrive back at the Rose & Crown at 7:45 and tell them we've arrived. It wasn't until 8:40 that we were seated. Yep, we waited outside, loitering on benches, not able to stray far from the pub, for about an hour. And of course, we were seated inside. They do have a special outdoor viewing area set up for people to watch who are seated inside, but you had to stand to see much of anything.
The show was quite good, but I don't know if it was worth that hassle. The food was only average in my opinion, and the wait was awful. That's just one person's experience with it, however. If I could do it all over again, I'd make that PS for about 7:30, not any later.