Hello Ken,
I'm thinking it is probably a difference between manufacturers, but can not say that with any certainty. I'm solely basing that on other examples of differences that I have been told were down to manufacturers production choices. See the following 4 photos.
Rob N will be the one to know for sure. I do have several repro 25pr manuals on the way, and they might shed some light, but I expect by that time we'll know from another member!
These are my brackets as returned from sandblasters, this afternoon. The simple one of them was still in it's original wrapping (VERY yucky, like treacle). The packing date on that one was 1979. Wonder if repacked then, or actually manufactured in 70s. If made then, a difference of over 30yrs between WWII manufacture and that one COULD just be design changes. In short, can someone plese put us out of our misery with this question!
I've emailed someone who has a good saddle which was advertised for sale some time ago. If still available, and affordable, I think I'll take it. Fingers are crossed. Wonder what the chances are of finding original trails?!
P.S: I've started making enquiries for quote/s on making the two U bolts for my brackets. Watch this space.