Object Cache Not Working

I’m trying to set up Object caching to speed up a highly dynamic website.

I’ve tried both Disk and Memcached options however I get the same HTML comments saying 0/0 objects cached?

This is the result from turning on debug:

<!--
Performance optimized by W3 Total Cache. Learn more: https://www.boldgrid.com/w3-total-cache/

Object Caching 0/0 objects using memcached

Object Cache debug info:
Caching:            enabled
Total calls:        0
Cache hits:         0
Total time:         0.0000
Page Caching using memcached (User is logged in) 
Content Delivery Network via Amazon Web Services: CloudFront: cdn.tpet.co.uk
Minified using disk

Served from: tpet.co.uk @ 2020-04-23 11:31:59 by W3 Total Cache
-->

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