William Gilbee Scott had a practice at 25, Bedford Row. The only building, apart from the How Gateway, we can find by him is the Salvation Army Citadel in Sheffield.
2016: via Facebook Neil Jackson told us of "a foundation stone on a building by him in High Road, Willesden, NW10. It used to be a church and for many years the local scout HQ. Now an Islamic school or mosque." Checking on Wikipedia we also found the Gower Street Memorial Chapel (now the Chinese Church in London); the London and Provincial Bank in Enfield.