Good news, good news!
I finally managed to get hold of the Salvation Army yesterday and they immediately arranged a viewing time to assess my furniture - today in fact. I had to spend last night and this morning clearing stuff. They arrived on the dot at the appointed time, plastic wrapped the furniture, and carted them off. I'm so glad that they're going to charity and not being disposed of!
The guys who came were very nice and polite (seeing as I was pregnant, one didn't even allow me to move my shoe rack to make space for them to shift the stuff), and in return, I filled out a feedback form for them. I am SO going to continue donating to SA.
Now I have lots of freed up space - there's room to move around in the workroom once again!