In 1898 the firm designed St Oswald's Chambers in St Werburgh Street, Chester, and this was followed by further buildings in the city. In 1902–03 Douglas built St John the Evangelist's Church, in the village of his birth, Sandiway. It was built on land owned by Douglas and he paid for the cost of the chancel and the lych gate. In 1899 the Diamond Jubilee Memorial Clock, constructed in open wrought iron, was erected on the Eastgate in Chester to commemorate Queen Victoria's Diamond Jubilee in 1897. In 1898–1901 Chester's public baths were built; this was an unusual work for Douglas as it involved specialist engineering work. During this period one of Douglas's most important secular buildings was designed, St Deiniol's Library, at Hawarden, Flintshire, for W. E. Gladstone and his family. The first phase was constructed between 1899 and 1902, and the library was completed in 1904–06. Around this time the practice was commissioned to work on two churches in association with Gladstone; St Ethelwold's (1898–1902) was a new church at Shotton in Flintshire, and additions were made to St Matthew's at Buckley, also in Flintshire, between 1897 and 1905. The other new churches built during this period were Douglas's only Scottish church, the Episcopal Church (1903) in Lockerbie, Dumfriesshire, and St Matthew's Church (1910–11) in Saltney, Flintshire. Alterations were made and furniture was designed for other churches. Douglas's last major project was the addition of a tower to his church of St Paul's at Colwyn Bay, but he died before this could be completed.