Liam rips up the manuscript of his novel and throws the pages in the lake, where they float on the surface. In the next scene at the lake, there are no traces of the pages on the water's surface. Given the number of pages it's likely that at least some of the manuscript would still be floating in the water.
The registration number shown on Sinclair's Jaguar Mkll was prefixed with a "D" which would date the car around 1996. The last year of manufacture for this model was 1969. Even if it were a personal registration, UK law prohibits using a number plate to make a vehicle look newer than it is. Thus there is no way this car could legitimately carry the registration number it displayed in the film.