In Lilith Norman's 1961 publication, 'Historical Notes on Paddington', she devotes a chapter to the origin of street names. According to Ms. Norman, most Paddington street names can be classified etymologically into 6 broad categories:
1. Descriptive - describing a characteristic of the street, such as Boundary st, Short st, etc. This category can include descriptions of the view, such as Prospect st or Bellevue st.
2. Royal - names honouring various royals, including Windsor, Queen, Regent, Victoria, etc.
3. Empire - those commemorating heroes of the British empire, including generals, statesmen and admirals such as Napier, Hopetoun, Belmore, Hampden, etc.
4. Nostalgic - British place names such as Suffolk, Leinster, Caledonia, Norfolk, Cambridge etc.
5. Military - battle sites such as Soudan (old spelling for the Sudan conflict) and Alma (from the Crimean war).
6. Local - honouring local notables and historic place associations, including early residents such as Gurner (for John Gurner), Heeley, etc; or old estates such as Duxford st (from John Gurner's house), Good Hope st; or even businesses such as Glenmore rd which took its name from the distillery (which itself took its name from a place in Scotland).
So the Duxford estate, as subdivided (the above image is from the Local History centre, the State Library has the original), took a couple of names from category 4 (Cambridge and Norfolk) and a couple from category 6 (Gurner and Duxford). So apart from being a posh nostalgic street name designed to sell some plots I'd speculate as a guess that perhaps the presence of the public school (built prior to the subdivision) may have influenced the choice of a more scholarly British place name. Or they just liked the sound of it.
