Well, I have been "Janet"
I used to work as a hostess for a very busy restaurant. Honestly, people should really be more aware and understanding that it is a complicated task to seat a large party in a dining space set up primarily for groups of 2 and 4. 14 IS a large party! You may think "oh, they can just throw 2 more chairs on the ends, but maybe NOT! There are fire codes, other safety considerations, and space limitations, it simply does not always work. It has NOTHING to do with bad customer service. Sometimes it just doesn't work. The fact that they WERE able to make it work to expand the table for your group size? You really under-appreciate that.
Also, if you know Rose and Crown has both indoor and outdoor seating (and they cannot guarantee which you get) AND you know you have an already much more challenging party to seat, and you made it even more of a challenge by adding extra people, WHY would you even think to complain about being in the sun? I mean if you were a small group of 2 or 4, perhaps you could opt to wait longer for another table, but you expected them move your group of 14? I'm sorry, but I don't think that's a very reasonable request.
The 2 "extra" people who planned late to join you, should have noticed your discomfort and offered to sit in the sun, or graciously broken off from the group for this one meal.