This traditional British pub is located in Westminster. The closest tube (underground) station would be Charing Cross and it is also quite close to the river as well. So personally, it is strongly suggested to have a stroll after having a wonderful meal at the pub.
The Wellington usually does not require any reservations/bookings because it is not fully occupied at most of the time. After taking a seat, you will be given a menu, which comprises main menu, set meal, drinks and alcoholic beverages as well. Seriously, it would be marvelous to try all of those dishes. But the most recommended dishes are Fish and Chips (though I haven't tried it), Fish Pie and Bangers and Mash. Other meal that are popular would be Ham, Egg and Chips, which is a kind of traditional English cuisine and Shepherd's Pie.
Overall, I would highly recommend this restaurant because the waiters/waitresses are very nice and hospitable and you will definitely be treated as in an inn or hotel. It is no doubt one of the best experiences I have ever had in England.