I'm a little dubious about ClearScore...
There are three bureaus: Equifax, Experian and CallCredit.
ClearScore apparently shows the Equifax rating, but I have an Equifax account too and it shows almost 100 points higher than ClearScore.
Mind you, my Experian rating is in turn higher than Equifax, despite listing the same accounts.
I also signed up to Noddle, as they show the CallCredit score... and I'm really pleased I did. I had an identity theft case a couple of years ago where a load of mobile phone contracts were taken out in my name. Equifax removed them from my file on request, but it seems CallCredit didn't. I'm now disputing that to get it fixed.
It's worth finding out which bureau the vendor/landlord was using and find out what score they have for you. You never know what you might find, especially if you see no reason why you wouldn't be accepted.