Hi @lansi6,
A warm welcome to the Bunnings Workshop community and thank you for your question.
Can I trouble you to upload a photo showing the side of the knob?
Are there any holes or seams anywhere that look like they relate to its removal?
Is there any brand or identifying mark on the tap that we could use to find an installation manual or design drawings?
Like @Noyade, I suspect where the blue ring runs around the knob there is a seam that will allow a cap to be removed.
You may need to use two multigrip pliers to hold the tap in place and rotate the cap to remove it. Use a rag, or some tape over the head of the pliers to protect the chrome from damage.
Another option is that you'll need to lever the cap off with a small flathead screwdriver. Look for a seam, likely near the blue ring, that looks like it allows something to be removed.
Give these two options a try and let me know how you go. I am happy to assist further if required.
Jacob
