Most G-Plan furniture was not designed by IKL. The G-Plan Danish line was designed by him. There are a few sites out there with attribution info that you could check your chairs.
Here is one: http://www.retrowow.co.uk/retro_style/furniture/g_plan/g_plan_ranges.php
Thank you for your comment, I have already looked through that site and am struggling to find any photos online of chairs which match these (obviously not including the covers as they were re-covered), there are some very very similar ones in terms of leg shape, seat angle, side bars and back rest, but nothing exactly the same...maybe they are very rare!
Anyone out there an expert in chairs of this design? or like the look of them!?
https://www.mustardvintage.com/products/copy-of-6-vintage-greaves-thomas...
these certainly look very similar in style..
Yes, those are similar. But yours have a more square seat and the ends of the legs have rounded "feet" instead of being tapered. And then there are those stretchers on the side.
A lot of Danish designer furniture was copied back in the day but with minor details changed to avoid legal problems, I guess. This happened even in Denmark and other Scandinavian countries, not just in the usual places for copying (wherever that was back then). I'm not saying that your chairs are copies, just that it's something to be aware of. If they are knockoffs, you're not likely to find much original documentation about them.
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