Can anyone tell me if this black plastic piece just above the sprocket can be removed, and if so, how? It would help greatly in getting to the side plug to replace it, if it could.
Sadly, no . You could pride off the plastic bit but it’s solid frame underneath. You have 2 options. Either something like this https://amzn.eu/d/9DX6jmC or you can just get an open ended spanner on the plug and once it’s loosened off you can just get your fingers in there. Be aware that if you use the flexible socket as per the Amazon link don’t use it to undo the plug completely, just use it to loosen it off or else you won’t get it out of there. It’s a PITA and really fiddly but once loose your fingers are best.
As above, but I have used a plastic or rubber pipe pushed on the top of the plug once it is loose. Makes it easier to rotate.
A butchered 14mm socket did the trick. A few flat spots on the socket, then in with a spanner to engage the flat spots to loosen it, then in with fingers to remove it.
