Help please with WhatsApp iCloud back up

[MissMarpleMyArse]

Long time lurker but first time post. I'm posting in this section rather than relationships as I need help with iCloud, rather than what to do if I find anything.
After some suspect WhatsApp activity from my husband a few months ago I set his phone to back up to iCloud. It's all been quiet since then but I've just remembered the iCloud thing.
I now want to look at what is backed up to iCloud. I tried deleting and reinstalling whatsapp and retrieving backed up data but it just bought one ancient message back
I'm now going in through >iCloud>manage storage> then it shows me backups, WhatsApp and a few random apps. What's app says some KB but when I click on it I only have the option to delete data.
Is there any way I can do this??
Like my username suggests, I'm a hopeless detective!
Many thanks in advance