How to retrieve multiple tracks from iCloud to iMac?

I have a problem which I'm hoping someone has an answer to. Go back a couple of months and I have iTunes with around 20,000 songs on it - 90% of which are cd rips and conversions from tape n vinyl that I did years ago. The rest are iTunes purchases and other random bits. I buy iTunes match as a back-up.

Then the pc with iTunes on blows up and I buy an iMac as a replacement. Using iTunes match and iCloud plus transferring some files over manually from an external HD, I know have all my music back (albeit with a lot of duplication) but the vast majority of my library is just sitting in the cloud. For various reasons I want all that music sitting back on my own computer again and I cannot understand why there isn't some easy/obvious way to do this. Anything that isn't an iTunes purchase has a cloud symbol next to it meaning I have to click this to manually get that track downloaded.

Do I really have to do this manually for the rest of the 17000 or so songs that are still in the cloud or is there some way I haven't thought of to get them all back in one go?

Begging for help here guys.