The 1881 census has him as William J Hassell b. Westminster, 0 years old.
Father William S Hassell, aged 22, Ipswich.
Mother Elizabeth Hassell, aged 21, Chelsea.
They are living with Elizabeths sisters family, her husband and their three kids.
They've spelt the name wrong, it should be Haszell, as it is on 1891 census. You wouldn't believe the spellings I have come across for Haszell. The original Haszell, Joseph was a hairdresser in Ipswich, moved to London around 1860 and his sons too became hairdressers.
But I agree, the WJH b.1881 is not my chap.