Having now bought food in Plug twice, I feel I can legitimately malign it! First time, I ordered a burger and they told me it'd be 20 minutes wait. After 35 minutes my number came up, I went to collect my food and got told "Sorry, they forgot to tell you we're out of burgers when you ordered"... Second time, I was waiting for 35 minutes for a pizza (they were only getting about 1 order out every 10 minutes), ended up complaining and skipping the queue
On a happier note, a few weeks ago I did have the good fortune of having dinner in Yak Yeti Yak on the sae street as Second Bridge. Moderate price, very good food, and large portions - I even liked their salad, which is a rare thing indeed. It's Nepalese, so kind of like Indian but not really the same. The guy has an amazing memory too, he remembered everything we all wanted without writing it down!
The Hare & Hounds up towards Lansdown does a very good carvery which isn't too expensive, and the puddings looked decent. The Fox & Badger in Wellow also does very nice food, but it's a bit of a walk just to go there (stopping off on a day walk it's nice, and there is plenty of parking should you want to drive). Cross Guns at Avoncliff is a nice little place as well with an excellent outside seating area by the river, and they do a very nice cream tea. All three are on good walking routes, with decent, well signposted paths.