If you are fascinated by Bordighera, it's history and the influence of the foreigners, you would enjoy reading Last Train from Liguria by Christine Dwyer Hickey. It's fiction, and it's set in the 1930s i.e. some 20 years after Clarence's time, but the backdrop of Bordighera feels similar to that experienced by Bicknell.
The book is captivating. Joseph O'Connor's review says "This is a big, bold, remarkably assured narrative that roams between 1930s London and Celtic Tiger-era Dublin, cleverly shifting its balance of perspectives and characterisations so that both those places lead inevitably to the fascist-era Italy that is really the novel's main setting. In 1933, Bella Stuart, the introspective daughter of a London surgeon, sets out for the country where Mr Mussolini is busy making the trains run on time. The plan is for her to be tutor to the son of the aristocratic Lami family - "there's a villa in Sicily and a summer house on the Italian riviera", and there is "some German connection, so you'll probably be popping off to Berlin". Fateful words for the whole of Europe, perhaps. Signora Lami turns out to be younger than Bella, her husband much older, a man who has "a face that is ready to die". There is a scene of Tolstoyan poignancy and unearthly beauty where Bella glimpses them bathing. This is a household as strange as it is crustily sumptuous. Its mistress refers to the servants as "frightful primitives". Even the sound made by the crickets seems different, somehow: "harsher and slightly neurotic"."