Just quoting the rules, Flying training requirements for the CPL:
"Applicants without a night qualification aeroplane shall be given additionally at least 5 hours night flight instruction"
It is difficult during the summer, however I can remember times where we have had to go night flying at 10 o'clock to finish complete a candidates night training.
Also in your original post you stated you do not need a night rating to get a CPL issued and that is certainly not true.