Off by one when searching for solutions. I managedThis seems to get what i want with these (inspired by stackoverflow/1831722):work.
/^.{234
    if(substr($0,234}${ 235, 12) ~ value}/)
    {
        print "5"4 - " substr($0, 235, 12);
        next
    }
    else
    {
        print "4 - NOK"
        next
    }
}
 
                