Ron,
That is not my photo, but snagged from an article written by Nelson Riedel and originally posted on the Buckeye Triumphs web site. I believe it is of Nelson's 76 TR6, and since I know him to be a very capable and careful engineer (not to mention a great technical writer), I think it's probably correct. I believe he got the idea for the spring from Joachim Gunst, the turnbuckle for adjustment was Nelson's addition.
At any rate, on a TR2-4, the bracket would be on the rear (transmission) side of the flange, then the slave cylinder would be on the engine side of the bracket. Meaning you can remove the slave from the bracket without disconnecting the hydraulic hose. That is the only way it will fit on a TR2-4, because there is no engine plate to cover the lower part of the bellhousing opening, and the factory plate to close the opening has a lip on it.
The TR6 Haynes I have, as well as the factory TR6 SPC, show the TR2-4 configuration; but the TR6 owner's workshop manual shows it as above. I actually believe either configuration would work; but since I have very little direct experience with TR6 (only Stags and the TR6 parts that will fit a TR3), I don't know that.
Yes, by "center bearing" I mean the needle roller that rides inside the end of the input shaft, with the output shaft in the center. When I bought my first Stag, it had exactly that symptom and that failure. Root cause, I believe, was lack of the special "dowel bolts" with precision ground 3/8" shanks that are supposed to do double-duty as both bolts and locating dowels between the bellhousing and engine rear plate (or casting on a Stag). Without the dowel bolts, the transmission slips out of alignment with the crankshaft and forces that little needle bearing to run at an angle, which overloads it.
Sorry if my terminology isn't quite right. I get confused trying to use American English to describe a British car; so I tend to make up terms on the fly. To me, the "input shaft bearing" would be the ball bearing that carries the input shaft in the front of the transmission housing.
PS, I don't think the pilot bearing is likely to be the source of the noise with the clutch engaged, since it only turns when the clutch is released.