IIRC the block is the same as the 138bhp engine models but the engines are far from cheap as tall or short blocks
Have you contacted citroen to see if they are willing to help a little? Even if its just to give a decent discount on an exchange block?
FYI A new block is £2500, there is no exchange item available but if your serious i can see what price without Citroen/PSA customer service i can get that down to
There are 5 crank bearing sizes a well from PSA which are roughly £9 each (*10 items)
Crank on its own is £1100 so IMO better to get the whole block as it is a short block already made up for you.
Also you can't get a bare block easily, but the original part that you have has also been superseded by a revised design, im guessing as its used in the 180 engines as well, it seems to be a common enough short block with only heads, injectors, turbos and bits and bobs changing as well as engine maps to get the various power outputs.