I am english so i can answer. First thing, most english are not mad about tea so make sure they want tea first! A good tea to get in a tea called Earl Grey. There are different types of Earl Grey but just get the normal original one.
The kind of tea an English person drinks on special occasion varies with the individual. However, green tea is preferred by many because of the powerful antioxidants it has. You can find more ideas on tea from http://www.my-teahouse.com/typesoftea.html.