Darwins

Good morning all, I have a problem, and I'm really hoping someone can advise me. My system has 4x3tb drives and 2x2tb drives. Recently I picked up 4x8tb drives A few days ago I pulled the parity drive out (3tb)and swapped it for a 8tb, as it was rebuilding, one of the other drives started show massive amounts of errors, and the time scale was something daft, like just over a year. So, I wake up this morning to the server off. It's my fault, as I have left it out of where it normally lives, as Im working on it, it looks like one of my dogs has tripped over the power lead. So I booted the system to find disk 3, the one with all the errors, is showing up with "unmountable: no file system" where the capacity should be. Unraid wanted to start rebuilding the parity, but I paused that, as I don't want a parity built with a missing drive. I do have backups of sorts, I thought about 90%, but after thinking about it, it was quite a few months ago, so it maybe as little as 70%. I still have the old parity drive, nothing has been added or changed since I started the swap Could I at this stage, pop the old 3tb parity back in where it came from, then replace the failed drive with a 8tb, and would it sort it's self out, or have I killed it? Its annoying, as I said on here yesterday about how long it was taking, and someone said I should have done the drive with errors first, but I just assumed from all that I had read, that the parity always had to be bigger. Any advice is really appreciated, Thanks