It's actually not a bad choice. The old shed is fox-proof, there are plenty of holes to fly through, it's dry and out of the wind, the shrubbery outside provides plenty of food - what more could you want?
When we visited last week the chicks had left the nest so I'm not absolutely sure that it was a White-browed Scrubwren family who took up temporary residence, but is anyone going to disagree with me? They are certainly resident in the garden, and there were two young birds being fed while we were there.
And as an aside, the side mirror on our car got a beating from a scrubwren while we were there. He obviously thought there was a possible rival in his territory. I've never seen them do that before. Fairy-wrens, yes. Scrubwrens, never.