I had an 84 230TE and purchased a Brooklands workshop manual from a company in California (can't remember the name for the life of me, though). Brooklands is a British company that does all sorts of automotive books -- workshop manuals, road test guides, etc.
In a quickie Google search of the web, I came across this company that appears to have this particular manual in stock: http://www.midlifeclassiccars.com/MERCEDES.htm
Good deal at $20. I think I paid $40.
In addition, the 230E was very popular in England and I'd be very surprised if you couldn't find a lot of information on British websites about them, not to mention an old genuine workshop and or parts manual on a UK auction site.