Can "they had it repaired" mean that they repaired it themselves? Why?
I've looked into this and can't find anything specific. Also, I've asked about a dozen people what they think and only one person said, "Yes."
Count me another "No" vote. The "had it" definitely implies arranging/paying for someone else to do it. Of course this includes the place where you bought it, so that you should have your iMac repaired at the Apple Shop rather than repairing it!