Not sure to be honest...
That blog 'may have to be decided at a later date', links to the original protest of HMRC against the administration.
Since the company was under a WUP, it could only be put into admin by a secured creditor.
It was put into admin by Chainrai - this was protested - and the judge said it was legal for him to do it... Ergo, he must be a secured creditor....
I'm no expert by any means, but this is my take on things, happy to be corrected [well, not too happy actually, because that would put Chainrai in the unsecured creditors camp, and making the HMRC debt percentage lower ]