Guests began the day in the park's giant Tree Tops Pavilion, which was transformed into a VIP hospitality area featuring a bar and barbeque that were available to use throughout the day.
As well as exploring the park's rides, attractions and safari reserve, Drp's guests could also partake in a workshop on the history of the agency and digital and interactive activities. A live steel band and performance from the Hipcats kept the music going throughout the day.
The evening saw guests enjoy a drinks reception in the dinosaur attraction, before being transported to Spring Grove house for a formal gala dinner.
The agency created a production equal to the main stage of Glastonbury festival for the showcase finale. The spectacle included a live choir, fireworks show and an appearance from the entire Drp team.
An after party on the lawn marquee rounded up the evening and featured a DJ, dancefloor and a set from Drp's own band, The Possiblers.
Dale Parmenter, group chief executive of Drp, said: "This 35th anniversary celebration event has been an extremely momentous occasion for all of us here at Drp. The team has put in months of enormous effort to ensure that this was a spectacular day and night for all and ultimately highlighted our promise to clients that 'anything's possible'.
"This milestone celebration has been by far the most elaborate and exciting to date and it's only going to get bigger and better. I am delighted to have shared our history and indeed our future with our guests and this has been a true testament to the hard work and creativity that our company is based on."
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