When Delboy is in The Nags Head, he takes an initial bite from his hot-dog, however moments later, just as Trudy announces "DEL!" He almost takes a bite again, but it is a full sized hot-dog again.
Raquel says she almost auditioned for a production of 'Aida' at the New York Met. Aida is an Opera by Giuseppe Verdi and the Met is the Metropolitan Opera. Raquel is an actress, not a classically trained Opera singer.
When Uncle Albert says that he's never heard any of the national anthems on the doorbells at the Olympics, Del says 'How many medals has Fiji and Borneo won?' Borneo isn't a country, it's an island split between three countries - Indonesia, Malaysia and Brunei. (Interestingly, Fiji have won an Olympic gold medal since this episode was aired, taking the rugby 7s title in 2016.)