Given the following context:

Lancaster's career designing for the theatre began and ended with Gilbert and Sullivan. His first costumes and scenery were for the Sadler's Wells Ballet's Pineapple Poll (1951), John Cranko's ballet with a story based on a Gilbert poem and music by Sullivan. His last were for the D'Oyly Carte Opera Company's revival of The Sorcerer (1973). In between, he designed more productions for the Royal Ballet, as well as for Glyndebourne Festival Opera, the Old Vic and the West End. It was a matter of mild regret to him that of the twenty plays, operas and ballets that he designed between the two, only one was for a thoroughly serious piece, Britten's Peter Grimes, for the Bulgarian National Opera in Sofia in 1964.Only two of Lancaster's theatre designs have remained in use in 21st-century productions, both by the Royal Ballet: Pineapple Poll and La fille mal gardée. In an article on the latter in 2016, Danielle Buckley wrote, "Lancaster's surrealist and stylized designs for Fille amplify the story's pantomime quality, and the exaggerated burlesque of its comedy – but the backdrops of fields that roll into the distance, bundles of hay, dreamy skies and village cottages provide the idealized, pastoral context that the story needs". Buckley adds that Lancaster’s designs have been criticised for locating the ballet in no particular time or place – "except, that is, of a 1960s London view of idyllic country life".Lancaster's stated view was that stage sets and costumes should reflect reality, but "through a lens, magnifying and slightly over-emphasising everything which it reflects". Sir Geraint Evans commented on how Lancaster's designs helped the performer: "[His] design for Falstaff was superb: it gave me clues to understanding the character, and reflected that marvellous, subtle sense of humour which was present in all his work."

answer the following question:

What is the name of the person whose first costumes and scenery were for the Sadler's Wells Ballet's Pineapple Poll? 

Lancaster