looking for an ellen mead who gave birth to Horace Mead who was adopted by Alice and George Britton - Bristol united KIngdom if anyone has any information - 1901 event

Do you mean that Horace Mead was born in 1901? Or that he was adopted then. There's a Horace J Mead, age 1, in Bristol in the 1901 census.

In the 1901 census tghere were three Ellen Meads living in Bristol, all unmarried:

Ellen Mead, age 24 (1877), born Westley Wilts, Parlour Maid Domestic
Ellen L. Mead, age 27 (1874), born, Thorne Somerset
Ellen Mead, age 23 (1878), Birmingham, Warwick, Cook Domestic

These are probably the same Ellen Meads from the 1880 census:

Ellen Mead age 3, daughter of William Mead, Sheep St. Birmingham
William Mead born 1839, London, Dipper & Bronzer

Ellen L. Mead, born 1874, Froome, Somerset, daughter of George H. Mead
George Mead born 1940 in Canada, Felt Hat Maker
Dwelling in 1880: Handforth, Cheshire, England

Westbury (?), Wilts
Ellen Mead born 1876, daughter of Henry Mead

Horace was born in 1900 and I have seen the census and he is then called Britton on the 1911 census re the adoption I amalsolooking for an Emily Britton who may have been the sister of Alice