I don't know if I'm missing something, or if it's a bug, but I can't find the talking statue to complete this quest

I've killed all the frogs & been though the portal & back again

I found a couple of statues & an empty plinth at the N E corner & it's the empty plinth that makes me think I've missed something important that I should do to make the missing statue appear?

I would appreciate help with this

Many Thanks
Em

Ahhh, I knew I must be missing something

Thanks Hickory :)