I have just finished wrestling with fitting pipework in the smokebox ..phew!
The pipework is of course all made and fitted without the smokebox in place but even so it is quite a squeez to get everything missing evrything else.
The main difficulty is how to get the smokebox on once all the pipework is in place as it is impossible to fit the pipework (except steam to cylinder passing through either side of the smokebox) with the smokebox in place.
The petticote/chimney gets in the way of the blower and ejector pipes.
I then found that the best way is to remove the petticote from the chimney liner fit the petticote to the pipes and then fit the smokebox and then screw the chimney liner into the petticote last.
By the way I gather that the ejector is unlikely to work because of the high back pressure from the long length of pipework into the chimney.
Another issue I found from fitting the smoke box is that the steam pipe covers cannot be fitted from inside the smoke box as the pipes from the superheater header are so stiff they will not move away from the end of the steam pipe. I found there is not enough head room to fit them over the steam pipe and slide in from the outside and in any event it precludes geeting any insulation in. I chose to split the covers into half lengthways and then split the halves into two giving four pieces. The back upper coukld then be slid into place followed by the back lower. Then put in the insulation and fit the outer top followed by the outer lower. The horizontal split is then covered by the band that goes around the whole cover. The vertical split is smoothed down and is not really noticable when painted matt black.