Customizr Theme Speed not satisfactory on mobile and desktop

I checked the speed of my child template at Google PageSpeed, I’m testing at it https://sandbox.peterwade.com/ and the mobile version was 66 and the desktop at 84. On the mobile version the main problem item seems to be…

Eliminate render-blocking JavaScript and CSS in above-the-fold content.
Your page has 3 blocking script resources and 2 blocking CSS resources. This causes a delay in rendering your page.

None of the above-the-fold content on your page could be rendered without waiting for the following resources to load. Try to defer or asynchronously load blocking resources, or inline the critical portions of those resources directly in the HTML.

Remove render-blocking JavaScript:
https://sandbox.peterwade.com/…3JNuuA6wgVEyPP630XVqpAxbce6JnNjUJZQEf.js
https://sandbox.peterwade.com/…_NrCrSz8xL1s8q1i9J1i1OLsosKCnWy83MAwA.js
https://sandbox.peterwade.com/…NLarUg_F1DfWM9Uz0cjPzsOkqSi3JzEsEyQIA.js
Optimize CSS Delivery of the following:
https://sandbox.peterwade.com/…iB2UBHfPLhBGct7gDs0uM8xmJDZPj8eA9uID.css

While I have no idea as to what to do about these problems, I do recognize that all the above are to do with Customizr code. Before I take the plunge and really customize it, have others had speed issues and how were they solved?

I am using a cache and their documentation seems to have nothing to say about speed. Since I only want to change to get the site responsive, speed is vital.

Thanks,
Peter