These STLs are for anyone who downloaded the previous versions of the D88 van files - the underframe had the holes to take the fastening pins for the W iron units offset by 2.6mm, meaning that they were binding on the axleboxes.  I have corrected the underframe STL in the main zip file but in case anyone has built the van with the misplaced pin holes these W irons (labelled D88 offset 2.6 on the bottom of the main stretcher) can be used to allow the van to run correctly.