Rose sends Cassandra a bottle of what appears to be Penhaligon's Bluebell perfume for her 18th birthday. According to the Penhaligon's website, the Bluebell perfume was first manufactured in 1978, whereas the film takes place around the early 1940s.
When Simon is drinking his tea in the first shot, he receives the cup with his right hand and then turns the handle to actually drink with his left. The handle switches back and forth in subsequent shots.
The cooked ham Simon gives to Rose is a prop, judging by the ease with which Simon lifts it, the sound it makes when he puts it in Rose's arms, and the fact that no juice or grease drips on Rose's arms or dress.