If the pilot's AH became inoperative in IMC while the aircraft was being crewed single pilot, it would be most difficult, particularly at night. to fly on the second AH, which in this aircraft is installed on the extreme right hand end of the instrument panel and well out of the normal eye scan of the pilot in the left seat.
Flight Safety Australia Issue 130 Winter 2020 has just been published. Page 46 revisits the Monarch Airlines Flight OB 301 that crashed during a night circling approach to Young, NSW on 11 June 1993. The article by Robert Wilson starts with the opening paragraph "In the bleak midwinter" and continues with "The destruction of a regional airline 27 years ago revealed widespread shortcomings at the heart of Australia's regulatory system."
See: https://www.atsb.gov.au/publications...aair199301743/
The Chieftain, circling in low cloud and rain descended below the circling MDA and into terrain. Manoeuvering for a circling approach was made more difficult by a missing cockpit instrument the Horizontal Situation Indicator or HSI on the captains instrument panel. It was missing because the autopilot computer amplifier that powered the HSI had been removed for repair. This meant that the pilot in the left seat had to look over to the right-side direction indicator.
A pilot who flew a similarly configured cockpit as part of the BASI investigation reported increased workload from this distorted instrument scan, and reduced flight accuracy. A ramp check at Sydney Airport six weeks before the crash had discovered this and led to the resignation of the chief pilot but changed nothing else. The new chief pilot was unaware of the inoperative HSI.
The OP's comment re the bad positioning of the second (standby) artificial horizon on the far right of the instrument panel and out of direct view of the captain in the Cessna Titan that crashed at Lockhart River, suggests nothing has changed in terms of CASA learning from the bitter experience of the Monarch Airlines Chieftain accident 27 years ago.
During flight in IMC the artificial horizon is a vital instrument for obvious reasons. So is any other AH installed for regulatory reasons. Why place the standby instrument in such an out-of-the way position on the instrument panel that, if forced by circumstances to using it in IMC, it will create it's own hazard in terms of pilot instrument scan?