Overall I am satisfied with this product, however, I have a few minor gripes.
1. The elastic band for holding the cover together broke immediately, it looked like the plastic fastener had previosuly broken and had been glued back together. I just glued it again with some resin and the problem has been solved. If it breaks again, I'll just keep glueing.
2. This isn't a repair issue but more about the product as a whole and so unrelated to BackMarket. While the height and width dimensions are adjustable and work well, the depth is actually quite limiting. My Samsung Galaxy Active 2 is not overly thick but it is a few mm too deep for the lower holsters and so doesn't fit. I taped a chopstick to the bottom of the tablet and now it fits so again, problem solved.
The only other thing is that the tablet feels a bit flimsy and the top and bottom halves slide around on eachother when closed, it reminds me of a cow chewing grass, but that is a desing choice rather than a repair-related issue.
With those things out of the way, this Folio keyboard is exactly what I was looking for. It lets me use my tablet as a mini laptop and it's really light. The bluetooth was easy enough to connect to, the item was well packaged in fully recyclable materials and it arrived as expected. You can't change the battery but it's supposed to have a two year life, I imagine this is something BackMarket replaced but I am actually not sure.
Thanks BackMarket, you will continue to be my first stop when looking for tech. (I also got the tablet here and it works perfectly)