File restore extremely slow

Coming from Crashplan Home, running on several machines including Windows Server 2016, Windows 10 and one Fedora 28 Server

Connected via fibre DSL running 200Mbit down, 100Mbit up

Moved to Wasabi for storage, currently trialling

Installed on Windows Server 2016, and is running as a service

Have set up a daily backup of some local folders for testing, around 150GB, this is working well and at good speed. Very happy.

Today I decided to perform a test restore of a 258MB file, it took 50 minutes - unacceptable, the same file from Crashplan took about 2 minutes

Duplicati reported no warnings/errors as far as I could tell

Checked against some of the files logged as needed from Wasabi, was able to download the 50MB files in a matter of seconds - no bottleck there

Server was completely idle during the entire time, rarely did processor or disk-IO get very high, and anti-virus didn’t kick in (using performance monitor to check processes)

What could be causing this? I have the profiling log but I’m not sure what to obfuscate before uploading it anywhere.