Getting SED b command to respect ";"

Question

Using MKS SED for Windows, this;

TYPE Q:\temp\allrequired.M3U | SED -En "/\\Curtain\\/!b;s_^.._Q:_p"

fails with

sed: label ";s_^.._Q:_p" not found in script

How can I get the b command to respect the command separator ";" and hence act with no label?

I'm aware there are alternatives to b in this case. This is demo of the b issue.

Currently I'm using this clumsy workaround:

TYPE Q:\temp\allrequired.M3U | SED -En -e "/\\Curtain\\/!b" -e "s_^.._Q:_p"