I tried to find the basket on **** but have no success.
Things you want to look at:
Tightness of the weave in the basket. This is much like cement in bricks - loose and poor, it will allow the basket to tilt and slope and loss shape
Thickness of the willow staves - not the corner posts. Thin staves - which are often used - will bend and flex, again allowing the baskets sag and tilt - collapsed bottom syndrome. Look for staves at least 1/2 - 3/4" dia -
Corner posts - these should protrude/be level with the weave of the main basket. The weight of the lid and person is thus directly transmitted via these to the ground. Where the corner post is below the basket weave, eventually the weave will bruise and the basket frame will undo.
Tightness of weave around the corner posts. Many of the baskets you see - show the upper corner weaving - with kinks and bumps - these willows were not softened correctly in the basket making process and this point of stress when drying out will fracture eventually.
As pointed out, my father, was considered one of the best basket weavers out - having made postal trays for HM and other heads - his baskets stand out a mile (well to me) - I am allows happy to post or give advice. Just wished I had a few more to pass down to my grand-kids.
Tight lines.
His relatives, well my relatives, still live in Poland and produce various wicker goods - I think mainly by outsourced workers. Don't mind if enough interest, how much a bulk order might be, provided it is made to Dads Standards:
https://olko.pl/en/ofirmie