I finaly, thanks to Pete have all the parts to fly these. However, in my BAT install I had the Bu-131B2 but even with the skin folder named correctly it kept leading to the He51C-1.
I dont know why but in BAT there are two listings ....
He51C-1 air.BU_131 2 NOINFO i01 SUMMER
BU_131 air.He51C 2 NOINFO i01 SUMMER
The Bu-131B2 air listing is....
Bu-131B2 air.BU_131 2 g01 SUMMER
Note the same " air.BU_131 "
So I reworked the classfile to be.....
Bu-131B2 air.BU_131B2 2 g01 SUMMER
Basicaly giving this plane it's own slot. If anyone else using BAT is having the same issue I did, please let me know and I'll send you my folder or post a link if it wont offend the makers of this plane.