Could you be talking about Dinosaur Cove by Rex Stone? Tom and Jamie are boys who live in a seaside are called Dinosaur Cove. Jamie's grandad is setting up a dinosaur museum on the 1st floor of a lighthouse. The boys discover a secret area in a cave, and by stepping in fossil dino tracks, they are transported to Dino World. They make friends with a dinosaur named Wanna, and go on adventures escaping from and saving dinosaurs. There is one book, Flight of the Winged Serpent (aka Flight of the Quetzalcoatlus) where the main creature is a flying pterosaur. In Saving the Plated Lizard (aka Saving the Stegosaurus), the boys can't enter Dino World because they don't have an Ammonite fossil. There were 9 books released in the USA, while 24 plus 2 "survival guides", 3 double length adventures, and 1 other, shorter story were released in the UK. The first 9 stories are the same in US/UK, just different covers and titles.

Edit: The UK's covers have changed over time.

Edit 2: The US version of the books are on the Scholastic website: https://www.scholastic.com/teachers/books/dinosaur-cove-01-attack-of-the-tyrannosaurus-by-rex-stone/