Replacing the SSD on my early 2015 MBP Retina

So my 13" MBP retina has been liquid damaged (beer spill!) and Apple want £968+ to carry out any of the repair work, however everything seems to work except that the SSD has lost the OS X or at least it wont boot up. So I installed El Capitan on a USB from my 2012 MBP and booted from that, everything seems to work fine, it's slow (obviously) but it does work, the wi-fi connects, the screen is fine etc, however - in the disk repair utility that you can boot from at the start, the internal SSD doesn't show up, does this mean it's irreparably damaged or is there another way for me to repair it? Failing that, are there any third parties that produce this part yet? I've scowered the web but I'm struggling to locate the correct one - I dont think it's the same as the macbook air SSD. Also, for any residue that's left on the logic board or any other part, is rubbing alcohol on a cotton bud (Q-tip) the best way to remove it?

If anyone can help I'd really appreciate it!!