The few 80xxx "big tanks" were not particularly well received on the Western when they arrived in 1962. In fairness it was very late in the day to find anything meaningful for them, and they were the locos from the LT&S Southend line after the electrification there, filthy and run down, in no small part from lack of fitters and general care there, and with all the issues arising from the Tilbury's bad water, which was the worst on BR and needed a high proportion of the fleet sidelined for washing out every day. Some were sent to Old Oak, not sure why, and may never have worked meaningfully again. Others went to Shrewsbury and the Cambrian, by the end of 1962 it must have been known these depots were being transferred to the LMR.
At Taunton it was likewise also a mystery why the 82xxx were sent on from Barry, where they had got early diesels. Essentially they replaced the 45xx small tanks there, which sat in a sad line west of the station alongside the Down Relief for a good while after withdrawal, like an illustration from the Rev Awdry's books, some of them getting on for 50 years old or more though still up to it, but also there were the large longstanding 41xx tanks which carried on, and top of the tree were four 61xx tanks from London, sent down displaced there by diesels. These were in excellent mechanical condition, and notably powerful and easy to run. They were even received nicely clean, at least one in lined green livery, a couple with the smokebox door hinge straps picked out in silver paint for some reason. A "London tank" 61xx is essentially to the same drawings as a 41xx, but the boiler is of a different steel alloy which allowed a higher pressure. By day they romped down the Minehead line, and at night, when most of the freight went down the main line, became the Wellington bankers. The 82xxx, see note above, were very poor in comparison, and the shed foreman had them steamed as little as possible. One does wonder if the crew on a heavy westbound freight pulling in to Wellington ever took one look at an 82xxx in the siding, said "ah, don't bother", and carried on.
The Britannias only lasted briefly in the West of England, having a trailing carrying wheel they were susceptible to weight shift to the rear when the loco tips back slightly with the drawbar pull, which is fine for adhesion with coupled wheels but wasted if they are not. They however had an even longer boiler than a King, a surprisingly compact loco, and this gave difficulties over Dainton, west of Newton Abbot, where the 1 in 36 gradient up to the summit is followed by 1 in 36 down the other side, something you don't get on the Lickey, or going up to Exeter Central, or other steep climbs. Full regulator and cutoff to blast up, water level in the boiler falls, tip over the top, water level at the rear firebox end drops right down (someone can do the calcs, I believe it is several inches), blows a fusible plug, has to come off at Totnes as it's now 1 in 40 up again over Rattery, Newton Abbot has to send a Hall pronto to take over, main line dislocated, talk with shed foreman for the driver - no thank you, Mr Riddles.
Just to pick out one of the litany of comments above about the 82xxx at Taunton compared to a 61xx ...