The operator will run the incentive to win £95 Love2shop vouchers for bookings made by an extra two days until Saturday (20 August).
A spokesperson for the touring and cruise company said: "The extension serves as an extra thank you to the trade, as it has clearly resonated with agents and we want to maximise the number of agents who benefit from it."
Head of sales and business development, Brad Bennetts, said the company has seen "such an incredible response" to its one-day 95th anniversary incentive.