the only one I could find was on Freecycle, sorry :(
Put it on ebay with a reserve of how much your Mum would be willing to part with it for, take plenty of nice pics, mark it as "retro" etc. and who knows how much she'd get for it? It's certainly an unusual looking tent, I don't even know if there are (official) tent collectors out there?
( I know collecting them seems par for the course on this forum, hehe)
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