Assembly help required please

[Charley Bourne]

I have Great War Miniatures 18 pdr.

Despite the absence of instructions the assembly is pretty self explanatory except for the 2 pieces pictured.

I think the larger piece is for sighting but I have no idea how either is put together.

I’ve e-mailed the manufacturer but have got no reply.
 
Does anybody have experience with this model please?

[dadlamassu]

Is this any help?

http://armorama.kitmaker.net/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=3681

[von Lucky]

I'm looking at the one I painted put together 5+ years ago. I remember those bits vaguely and I must've given up as I can't find them on the model

I think the view finder goes on the left (as per dadlamassu's first photo). There's a dimple on the model. The other part - no idea.