When is the best time to book?

Hello. I've been trying to book a pitch for a weekend in June on a club site all day, and haven't had any luck. Because I need to discuss a couple of things (like arriving late on the first day and using the late arrivals area), I wanted to make the booking by phone. It is also my first time at booking a CC site, as I've only just joined the club. However, I have rang the club booking number repeatedly and have sat on hold for ages with no answer. I have also tried the site directly, and also get no answer. I am wary now of ringing the site itself at this time, as they're probably all busy pitching people for the weekend.

What do you advise? Are there better times to call the site/club than others? Is it always this busy calling the club site booking number? For info, the number I keep calling is 01342 327490 and I've been trying it since 9am this morning and haven't got through once.