Screen overhang is prob more of an issue during hoovering in the minds of the designers I don't know lol Cheers for doing the math. I agree with you a 75" would look great, only 5" at the sides is nothing anyway (said the actor to the bishop!)
The table is 150cm which is 59 inches. 65 inch TVs are around 57 to 59 inches wide, so if you want no overhang, it'll go up to 65 inches. But a 75 inch looks really nice on it and any screen overhang doesn't make it look stupid.
My panasonic ex750 50" feels blooming heavy, although I haven't actually looked up the weight. I think the reason they list the max size of 55" is because that's the width of the actual unit and screen overhang at the sides is to be avoided if poss?
This will support 75 inch TVs easily. Seen this in a local store and they had a 75 inch TV with wide legs on it, with room to spare. I don't think there's a single consumer TV above 50KG in the UK market right now. I think the heaviest would probably be the Sony 85XF90, which comes in at 45KG, so this stand would work for pretty much any TV.
Did you try Pcworld aswell? Could be same stock list not too sure