Gussets ! ! !
OK I give up, what, where and why?
I have found them on the fret but haven't a real clue which way round they go and at what position. I think I have found the lower front ones  and rear ones  on the plan drawing but at what height? The top leading ones  are so small - blink and you will miss them. Anyway I did take the precaution of punching out the rivets on [54 & 55] before removing them from the fret.
The instructions state "on this loco they are rather prominent, especially the leading ones which protrude through the steps". I cannot see how the small top ones can, yet still have a point of attachment. The lower ones will get in the way of the buffers and despite the hole will make attaching the body near impossible. Sure I know that the instructions say to add the buffers first but I do not like adding buffers and then clogging up the springs before painting.
To add to this I have been unable to see any of these on the prototype photos and wonder if they will be visible on the completed model. The instructions also state "often these are ignored".
I can see why.