I was actually considering starting a thread on this subject, mainly the Romanian 56s and exactly why they were built there (not really surprised it was part of a wider polictical decision) given how I had heard only bits and pieces about it across several threads and had alway been curious as to the answer. 56s being one of my favorite BR diesels is also a reason lol
The RCTS has a feature on the Romanian 56 delivery trains from Harwich to Tinsley and the locos which hauled them once on British shores under the
Diesel Dilemmas banner (link below). 31s & 37s featured heavily on these moves, but one 25, 47 and at least one pair of 20s are also known to have featured as locos changed over en-route.
features.rcts.org.uk
At the risk of going off topic surely the Class 56s must have ended up being generally more expensive than planned. As well as the first thirty locos and the issues discussed here the last twenty locos were built at Crewe. Switching production there to let Doncaster reorganise for Class 58 construction can't have been cheap. Did it lead to any delays in delivery of the last twenty locos or any differences between them and the 85 Doncaster built locos?
Am not aware of any differences between the bulk of the fleet (the 85 Doncaster-built machines) and the last 20 members (the Crewe-built examples) aside from the builder's plate, but the upheaval and reorganisation involved no doubt had some bearing on the last 56s not entering traffic until late 1983/early 1984 (last-built 56135 didn't enter service until January 1984 iirc), over a year after the first Class 58 had been delivered.