How do I print a string using client.print or similar ?

I'm developing Web Server that amongst other things will show the boot time for my UNO server.

My function below sends a string happily to the Serial Monitor e.g. Serial.println(boottime);
but I can't duplicate the same string message display to the browser say using client.print(boottime);

earlier in the program boottime is declared as a string as follows:
// declare timestrings
String boottime, time_now, h_stg, m_stg, s_stg, d_stg, mth_stg, yr_stg;

Any ideas ???

void boot_time_string() {  // build boot time string
h_stg = String(hour()); 
m_stg = String(minute());
s_stg = String(second());
d_stg = String(day());
mth_stg = String(month());
yr_stg = String(year());
Serial.print(F("This web server commenced running @ TIME: "));
String boottime = h_stg + ":" + m_stg + ":" + s_stg + " and DATE: " + d_stg + "/" + mth_stg + "/" + yr_stg ;
Serial.println(F("  "));

It seems client.print can only send text between quotes e.g. client.string(“qwerty”);
basic variables like integers BUT not long strings like boottime in example above BUT can send constitute parts of a string a part at a time e.g. client.string(d_stg);

Here is my code in the ethernet part of my code:

client.print(F("Web Server was booted at DATE: "));
          client.print(F("    TIME: "));
"); // br: creates a single line break in a block of text