I've found the family in the 1911 census now, where they're listed as follows:
William Louis Miller, head, 40, Pork and Provision Dealer, Wareham
Rose Miller, wife, 37, Poole
Ivy Rose Miller, daughter, 14, School, Poole
William Ewart Miller, son, 12, School, Poole
Frederick Lionel Miller, son, 7, School, Poole
Leslie Stuart Miller, son, 2, Poole
John Keith Miller, son, 1, Poole
Elsie Stone, servant, 16, General Servant, Poole
There also appears to be a daughter Olive G born in Q4 1913, but I haven't yet found more recent details of the family.
- David.