Kimric

A bunch of things are different. Better grade of reeds, better button material, better bellows and better construction (hardwood rather than plywood with celluloid skin).

Not a bad idea to apply a tiny amount of lithium grease with a toothpick to the axle area where the guide rubs the arm since aluminum against aluminum wear surfaces do not fare well even with light use unlubricated.

I have a 2 row one that is really similar. The brass action is similar to a wheatstone but the buttons are glued to the ends of the arms like a wood action instrument. bellows are pretty good quality and has a tag in the bellows from a store on Mongomery St. in San Francisco that is 50+ yrs gone.

The lining is most likely just cotton velvet. Joannes won't have a very good selection but you don't need much so perhaps online might be better. https://www.fabric.com/home-decor-fabric-velvet-fabric.aspx Keep in mind that upholstery velvet will be slightly thicker (mm or so) so if your instrument is a snug fit take note.

I have been wondering about the interest in Anglo boxes in other keys. I have a supplier of 2 row Chinese models that are unique in that the reed blocks are removable like a conventional accordion,and that I have the entire stock of Weltmeisters old warehouse of reeds sitting on shelves in the back of my shop. B/C anglo anyone? These would sell for about $300 USD with the wandering button problem the have fixed.

I get these new in the shop like this, so it is not always age related. I rebuild these as soon as I get them since it is a constant problem.