There is so many E34's in scrap yards up and down the country, getting a complete strut is easy and cheap if you are going to DIY. Pay a garage to provide a strut and other new bits and it isn't worth it. I bet for £50 you could just go to a scrap yard and unbolt a complete strut with all the arms etc and just bolt this up to replace the damaged part.
Pesronally I'd sell the Touring and take of any good bits from the damaged car and look for a 24v 525, like this
http://www.pistonheads.com/sales/127970.htm and add on the bits you want to.