As for the battery being sold with the top case, I have less of a problem than many with this as it's difficult to ship the batteries safely or remove or replace them in these machines. That's a design flaw which I hope they will sort out at some point but at the moment it is what it is. What is objectionable is that the rebate for the part that is returned is really really poor if you use the self-service repair store. £510 spend for an £85 return. If that's just the battery that's gone it's a rip off.
My risk is that if I have a problem with mine, I will just buy another one though. It paid for itself in under 3 days when I bought it.