3"/75mm round or square washer (Kirkstall LS4)

Hi folks...
I picked up a chair from one of the kind people here but sadly it needs a small repair.
Oddly I had the same chair in my own house and it had the same fault...
One of the 2"/50mm wooden legs has dug into the base of the chair and last time it was a bigger hole.
On that occasioni bolted the leg to a larger plate and screwed the plate up with 4 good sized screws. The only problem then was a little rocking as one leg was 3mm longer than the others...

So...
This time a plate larger than the 50mm/2inch foot will resolve the problem...plywood would work also... and 2 pieces or 4 pieces to avoid the wobble...

I'm a big heavy guy, I might have caused the dent myself... so I can't use the chair till I effect the repair.
Hope someone has something, but I can only collect in a small radius due to my cars poor fuel consumption
Thanks in anticipation