They have almost all of the contracts for delivering passports, official documents, etc. Clearly governments trust them.
I've only experienced them when I sent my passport off for a Ghanaian visa, which was fine. Came back on the date they said at the time they said.
The secure post is not dealt with by the "own car" drivers.
They've been dealing with legal / financial documents for as long as I can remember and are very good at it.
The opening up into new markets model seems to replicate that of myhermes, but from what I can tell it's all separate to the main business (in terms of the delivery network).
It's either this lot or hermes