Page Load Times Suffering – Please Help

Hi,

I have been having a lot of problems with my site, https://wilddigital.co.uk, recently and so I have been running regular Pingdom site speed tests.

Two things are showing up consistently as slowing down the load time and I don’t know how to fix them:

The first is that a deleted header image is showing up as a 404 causing the server to search in vain for it for usually between two and three seconds before giving up and moving on to loading the rest of the site. (link: /wp-content/themes/balance/images/header.png)

This image has been permanently deleted from the media library and has since been replaced with https://www.wilddigital.co.uk/wp-content/uploads/Wild-Digital-Logo-Header-250×136.png which is working fine as the header / logo image.

Is this a cache issue with the host? Do I need to clear the host cache? I use WP Super Cache and see that I can perform this function via the plugin. Are there any dangers in doing this? All of the issues with the site and server have made me incredibly nervous.)

I set up a redirect to stop the 404 from happening and got two logo images showing up in the header for my troubles… but it speeded up my load times!!! I am perplexed beyond belief by this issue… I thought permanent redirects were just that, and that it was only posts and pages I needed to worry about…

The second issue is seemingly with the CSS edits I’ve made. I think I have formatted the edits correctly, but I’m not sure about the heading tags (h1’s, h2’s etc…).

Here’s the link that the Pingdom test displays next to the issue:
https://www.wilddigital.co.uk/?custom-css=1&csblog=1&cscache=6&csrev=56

You can see the whole report here:
https://tools.pingdom.com/fpt/#!/d4LXNh/www.wilddigital.co.uk/

Please note, the problems I have been encountering recently with the website are due to server outages and W3 Total Cache becoming corrupted for some reason, which in turn broke a load of other plugins… a nasty business that I haven’t completely recovered from…
If you know any great diagnostic tools to figure out what’s broken with a WP site and plugins I’d appreciate it if you’d share it with me.

Thanks in advance for any help and advice.