<modsnip - not victim friendly>
In M’s favor, police have said he’s not a suspect and so there must not be any obvious and compelling evidence that points at him.
For me, a few extra details re relationship status and living arangements etc would go a long way. But if they were in the throes of a break-up, that might complicate matters and a bit of speculation along those lines kind of tips his behaviour into the normal range....for eg: Perhaps Toyah was expected in PD after the walk at Wangetti to visit the pets they shared and she did not arrive when expected. If the relationship was on the rocks, M as an ex, might not have felt he had the right to try find out where she was...pride/indignation kicking in? So he goes off walking a Spring Falls and while there, loses his dog. He returns home, Toyah has still not turned up and so he calls her folks. It makes sense the if the plan was for her folks to retrace her normal trip north and see if she has, for eg, a flat tire in a carpark someplace and for M to stay in PD waiting for her to show. <modsnip - not victim friendly>