Well the point of an RF is to use it on TV's that only have an RF Output. I realised that it was a bad idea. My TV does not have a scart connection there I cannot use a scart cable.
I only said that you don't use the rf output when you have av composite available, what I would complain is that the av output built-in from the amiga 500 should be in colour so we don't have to use the Amiga 520 adapter. So in a way you have to use the adapter if you want colour on composite.
In Australia we don't have scart tvs or connections to it but you can import them but at a hefty price.