Glad this has been bumped of late.
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@Jon (although a little bit more retro) I've been using a macbook pro 2009 with very little issues (it has it's quirks now but everything is workable including trackpad + keyboard).
Just today, the platform for my teaching company has been updated and sadly has outgrown my laptop's capabilities OS wise, it needs Sierra or above and I can only run up to El Capitan. Some could say I'm indoctrinated but 11 years of solid service speaks for itself so I'm looking to go down this route again. Can see refurb models being mentioned above, could anyone please let me know what the best outlets are? Speaking to a mate today he said his missus got a macbook air from PC world, I legit didn't know they sold them there considering the name of the shop, any advice on where to look (and where's gonna be reliable) would be really appreciated. I'm not against buying one new if it's going to last me another sizeable chunk of my life.