Cloud Storage Usage

Not particularly Lightroom related but there didn't seem to be a better place for it and I guess you guys will be more familiar with what's usual and what's not.

I've used Lightroom on and off for years but all I have in my cloud storage at the minute is 36 raw files of around 35mb each from a 5Dmk4.  I calculate this is about 1.2gb of data but my account is showing that I've used 4.2gb.  I have nothing in deleted (I've permanently cleared everything), nothing waiting to sync or with sync errors, nothing in other folders I've forgotten about - just those 36 images.  I had 10gb+ a couple of weeks ago but I've downloaded and backed up all of those images, they're gone from the cloud, and all I have is the new images from the last couple of weeks.

How am I using so much storage?