When Edward tells Freda that she should have checked up on him with "Somerset House", he is referring to the fact that it then housed the Public Records Office where one could see any deceased person's will.
Phillip refers to Broadmoor, a high security British psychiatric hospital, which has housed some rather notorious inmates over the generations.
Edward's convertible is a 1955 Sunbeam Mark III.
The Health & Strength magazine Edward is reading in the seaside restaurant is a real periodical. It is the April 14, 1955 (volume 84, number 8) issue, featuring Reuben Govender from India on the cover. The price was 1 shilling (1/20th of a pound, or about $2.00 in 2022). The use of this magazine may allude to Edward's sexuality.
Charlotte's automobile which Edward repairs is a 1950 Jaguar Mark V.