Download issue

I had the original HZD on disc for PS4. Completed, uninstalled, sold the disc.

At some point, the complete edition became available on PS+, and I "bought" it at the time.

Now I am trying to install the complete edition on my PS4, but I am only getting an option to download the Frozen Wilds DLC, or pay £34.99 (well currently £17.99) to buy it again.

However, on my PS5, I can download the whole complete edition no problem.

And yes, both of these versions are the PS4 versions, NOT the PS5 versions.

So how can I go about getting it installed on the PS4?