Probably mythically, Bognor Regis is known to most people because of King George V (1865-1936). He had an operation in 1928  and it was decided he should convalesce at Graigwell House in Bognor.  As a result, he was asked to bestow the suffix Regis (of the King) on Bognor. When the petition was presented he supposedly replied, 'Oh, bugger Bognor.' But the petitioners were told, 'the King has been graciously pleased to grant your request' which is why it is called Bognor Regis. A slightly different version of the  incident is that the King, upon being told, shortly before his death, that he would soon be well enough to revisit the town, uttered the words 'Bugger Bognor!' (Wikipedia here). So when the Stevens family went to Bognor (the book was published in 1932 and must be set around 1930) it was then enjoying its new association with royalty.