Although it is less than an hour on the train from London, the village of Great Missenden has not changed much since I first visited it twenty-five years ago. From the station I walk down the high street, past banks, shops and pubs, some of which have been there for hundreds of years. There is red brick, lots of Tudor timber, some tasteful blue and green washes. And what is that up on the left? A house with a huge and strange shadow on it. Wait a minute … it is not a shadow. It's a pale outline that I recognise: a tall figure, very tall – the size of the house; he is draped in a great coat, holding a case and trumpet-like tube. It's the BFG, lightly sketched on the front of the building. Below him are the words: ‘IT IS TRULY SWIZZFINGLY FLUSHBUNKINGLY GLORIUMPTIOUS.’ But this is no crude graffiti, and no normal building. It is an old coach house converted in 2011 into the Roald Dahl Museum and Story Centre. It tells Dahl's amazing life story, showcases much of his memorabilia, and inspires children to create stories of their own. The interior of Dahl's legendary writing hut was carefully moved here, piece by piece in 2012, to preserve it and make it accessible to viewers. However, the museum is not my destination today. I resist the enormous temptation to pop in, for I know if I do I will be there for hours, lost in another world.

I continue past the museum and down the high street. A couple of miles further is St John the Baptist Church at Little Missenden. It is a beautiful Saxon building, dating back more than a thousand years. Inside, I see pale twelfth-century frescoes on the walls, and the original Roman bricks can just be discerned, incorporated into later arches. My eye is drawn towards a wooden puppet-like statue, brightly painted and sitting incongruously just above the front pew. I go to take a closer look …

Although the Dahl family were not ardent churchgoers, St John the Baptist Church at Little Missenden is where all the children were christened. The Norman church of St Peter and St Paul in Great Missenden was closer to the family home, but for Dahl the petite and pretty building at Little Missenden, with its extraordinary frescoes, held a greater attraction.