"Metering is transformer mounted"
I've never seen that.
Please upload pictures to ECN.
In America the rules for the Poco and the User are different, as the Poco is not covered by the NEC.
"electrical shack"
Is this a mine?
The new conduit... is it a buried run?
In legalese, at which point does the installation become owned by the User?
In many situations, the demarkation point is the disconnect, itself... the location of the meter... not so important.
Every jurisdiction has its twists and turns on such matters. This is why they issue 'style sheets' // handbooks detailing E X A C T L Y how they want a (User's) Service to be laid out.
The few feet from the 1200A disconnect to the twin, fused, 600A disconnects may be considered covered under the tap rules.
In industrial situations, many of the hard rules are waived with the proviso that ONLY qualified personel will able to enter the electrical spaces.
It's as common as dust for Poco's to consider their underground secondaries suitably protected -- without fusing -- so long as they only stub out of the ground into suitable disconnecting means.
I've seen residental Services that featured twinned 200A panels feed by a 400A secondary -- with no unifying disconnecting means at all. This set up falls under the six OCPD rules.
Digging in frozen ground sounds like a real pain....
