So, not wishing to put potassium permanganate through my machine I decided it was simplest to just swap the number 2 and 6 bottles over. I'm highly unlikely to use a 6 bath process for quite some time so this seemed like the simplest option.

Here are the screws that need removing to allow access to the pipework and bottles, they're ringed in green:

Next the drain cock handle needs to come off, it just lifted out on mine:

Here's what the exposed pipework and bottles look like:

The removed bottles - I disconnected the smaller reclamation system tubes, and pulled the entire large feed pipes including gromets out of the bottles - the gromets were pretty 'stuck on' and I didn't want to tear them or risk breaking anything through brute force:

Lid removed, it's just held on by a small screw on the collar - you can see how gunked up the bottle is:

The dirty lid and collar:

And after a scrub:

Here's a gromet after removing with the help of some liquid soap, this was then reinserted in the bottle top prior to inserting the chemical feed tube:

All back together: