Question: What British actress born in May started in a television series set in a fictional Sussex coastal town? 

Context paragraphs:
Mapp and Lucia (1985 TV series): Mapp and Lucia is a British television series, set in the fictional Sussex coastal town of Tilling-on-Sea and based on three 1930s novels by E. F. Benson.  It was produced by London Weekend Television, filmed in Rye (on which Benson based Tilling) and neighbouring Winchelsea in the 1980s, and starred Prunella Scales as Mapp, Geraldine McEwan as Lucia, Nigel Hawthorne as Georgie, and Denis Lill as Major Benjy.  The script was by Gerald Savory.  There were ten episodes, (which aired in two series of five) broadcast on Channel 4 in 1985 and 1986.  These have been repeated over the years, most recently on ITV Encore in 2015, shortly after the broadcast of the new BBC adaptation "Mapp and Lucia" and the death of Geraldine McEwan.

Georgia Mackenzie: Georgia Mackenzie (born 19 May 1973) is a British actress born in Abergavenny, South Wales .

Tilling (Sussex): Tilling is a fictional coastal town, based on Rye, East Sussex, in the "Mapp and Lucia" novels of Edward Frederic Benson (1867–1940).

Eastbourne Bandstand: The Eastbourne Bandstand is a bandstand on the seafront of the East Sussex coastal town of Eastbourne, with an attached colonnade and viewing decks.  Built in 1935 to the designs of the Borough Council Engineer, Leslie Rosevere.  Neo-Grec style, constructed of cream faience with some decorative blue, green and black faience, with its unique semi-circular design and blue domed roof; there is no other in the United Kingdom.  It has a main arena, middle and upper balconies for seating and originally seated 3,500 but with current health and safety laws this has been reduced to 1,600.

Juliette Gruber: Juliette Gruber (born 1965) is a British actress born in the United States, but who moved to Britain at the age of one.  Gruber studied at Trinity College and got a job at Royal National Theatre as well as in various TV things such as the military show "Soldier, Soldier" that aired from 1991, the police show "Between the Lines" 1992–1994 and from 1995 in "Kavanagh QC" about a judge.  From 1995 she was a school teacher called (Jo Rowan, née Weston) in thirty-eight episodes of the ITV TV Series "Heartbeat" until 1998 when her character moved to Canada with her husband, played by Nick Berry (born 1963).  Juliette left the series and settled in southern France with her boyfriend.  Since then, little has been heard of her.  She is the niece of Hollywood actor Walter Matthau (1920—2000), who was married to her mother's sister.

Hayley Atwell: Hayley Elizabeth Atwell (born 5 April 1982) is a British actress.  She is known for her work in stage productions such as "A View from the Bridge", and onscreen, she is often cast in period pieces, such as the 2007 thriller "Cassandra's Dream", the 2008 drama "The Duchess", and the 2010 historical drama miniseries "The Pillars of the Earth".  She is best known for her portrayal of Peggy Carter in various films and television series set in the Marvel Cinematic Universe, including the lead role in the ABC action-adventure series "Agent Carter".

Mapp and Lucia (2014 TV series): Mapp and Lucia is a British drama television series that was first broadcast on BBC One from 29 to 31 December 2014.  The three-part series, adapted by Steve Pemberton and directed by Diarmuid Lawrence, is based on E. F. Benson's Mapp and Lucia collection of novels.  The series features an ensemble cast, with British actresses Miranda Richardson and Anna Chancellor playing the eponymous characters Elizabeth Mapp and Emmeline 'Lucia' Lucas.  It is set in the Sussex coastal town of Tilling, based very closely on Rye, East Sussex, where it was filmed and where Benson lived.  Although attracting modest viewing figures, the series received positive reviews from critics.

Natalie Gavin: Natalie Gavin is a British actress born in England.  She has starred in several British television dramas and comedies.  These including BBC dramas "Prisoners' Wives" and "The Syndicate", as well as the Channel 4 comedy drama "Shameless".  She also appeared in the 2014 The Old Vic production of "The Crucible".

Jackson's Wharf: Jackson's Wharf (1999–2000) was a New Zealand television series created by Gavin Strawhan and Rachel Lang.  Set in a fictional coastal town, the series told the story of a sibling rivalry between brothers Frank, the town cop, and Ben Jackson, a big-town lawyer.  After inheriting the local pub from his recently deceased father, Ben returns to the small town with his family, with his arrival bringing its fair sheer of drama and conflict to the small township.

Geraldine McEwan: Geraldine McEwan (born Geraldine McKeown; 9 May 1932 – 30 January 2015) was an English actress who had a long career in theatre, television and film.  Michael Coveney described her, in a tribute article, as "a great comic stylist, with a syrupy, seductive voice and a forthright, sparkling manner".

Supporting paragraphs: Mapp and Lucia (1985 TV series) Geraldine McEwan
Answer: Geraldine McEwan