Why don't you make your own developer such as ID13 or Ansco 70 ( you could find the formula here http://unblinkingeye.com/Articles/LithDev/lithdev.html )
It only contains easy to find product. It stock well I use to prepare 25 liters of Solution A and I prepare solution B By 5 liters only.
Hope you have good result with your lab in Rotterdam
Best