Saving photos stored in Whatsapp and not camera roll

Hello,

Sometime in October my Whatsapp photos switched from storing on 'camera roll' to being within Whatsapp. I did not realise this until recently and want to download these photos to my PC. I have since changed my Whatsapp settings back to storing photos on the camera roll but I want to save all the missing photos. They are NOT on icloud as icloud is switched off. The photos are not visible using MS Photos app and they are not visible using Window explorer. Can anyone tell me how to transfer these 'lost' photos?
thank you