*** UPDATE ****
Just did a little more research (didn't do too much when this originally occurred as it as after 2:30am in my timezone !!) and found the following:
and also:
Now I'm guessing that perhaps this is just an AWS implementation that the Piriform Devs are utilising to deploy the CCleaner for Mac download.
(It's unfortunate that the name of the AWS service for distributed Content Delivery (Cloudfront) also corresponds to a previous virus/malware !!)
Would've been really handy if there was some sort of note to expect this issue - perhaps an update to the website for future (Mac) users experiencing the same problem ??