Hi - Sorry to be a complete noob but I decided to try Cloudflare DNS servers and all seems fine but despite a fair amount of Googling IPV6 is confusing me.

I cannot find what to enter into the "PREFIX" field.

I also have no idea if trying to configure IPV6 is a complete waste of time (I'm with Spark)

The other options in my router for IPV6 "Configuration" are -

"Auto-Configure DNS"

or

"Auto-Configure Subnet"

or

"Manual" What I'm trying to do.

I've configured IPV4 as usual no problems just entered the server addresses.