Was initially processing through Kleopatra/GPG4Win on MS Win10 for previous outputs and didn't realise instructions were available. Ran
gpg --import solus-releng-pub.gpg
gpg: key 618EB3600BD32D59: "Solus (Release & Engineering) <releng@getsol.us>" not changed
gpg: Total number processed: 1
gpg: unchanged: 1
So that part worked but the verify didn't:
gpg --verify Solus-Budgie-Release-2024-10-14.iso.sha256sum.sign Solus-Budgie-Release-2024-10-14.iso.sha256sum
gpg: can't open signed data 'Solus-Budgie-Release-2024-10-14.iso.sha256sum'
gpg: can't hash datafile: No such file or directory
Basic issue turned out to be when clicking the Solus-Budgie-Release-2024-10-14.iso.sha256sum file link, it displayed rather than saving to the downloads directory, so was missing (other links downloaded). After saving:
gpg: Signature made 10/15/24 09:39:40 AUS Eastern Daylight Time
gpg: using RSA key F5F6685CAF5559771D9CCB92618EB3600BD32D59
gpg: Good signature from "Solus (Release & Engineering) <releng@getsol.us>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: F5F6 685C AF55 5977 1D9C CB92 618E B360 0BD3 2D59
So all good. Thanks for the response.