Just to update this thread, it seems that Dayco 89054 is now readily available in Australia. I'm ordering a couple from my local auto shop.
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I picked them up yesterday & they're identical to the original LR pulley - plastic with the bearing moulded into place.
$20 each so if they last 20 years like the originals, I'll be happy.
Actually, if the rest of the car lasts 20 more years, I'll be ecstatic!