How can you search for "others in the household"? I've not found any way to do this other than paying, and even then, it may be the wrong family.
The "search address" function does not seem to be much use either since it is not possible to enter a house number.
To correct myself, you can search for others in the household, as long as they have the same surname. Here's how you do it, with one of my examples:
1. I know I am looking for Albert Garrard, born 1888, and last seen living in North London in 1901. I find two born within 2 years of 1888; one in Lambeth and one in Shoreditch. I'm not sure which one is mine - so let's guess it's the Shoreditch one.
2. Search again, but type in "Shoreditch" in the "Residential Place" and remove the year of birth search criteria. Make sure only one name comes back - in which case he is the only Albert Garrard in Shoreditch.
3. Remove "Albert" from the Personal Details first names, and add "Albert" to First names in "Other members of the household". You will then see everyone else in that household with the surname Garrard.
4. This is the right one! I recognise most of the names from 1901. I discover that two more siblings have been born since then.
It might be the case that Step 2 brings back more than one match. In which case, if you know someone else who would be in the household (a sibling, a parent, etc.) add them to the "Other members in household" until you get only one match with no year criteria, then eventually add both names to the "Other members of the household" forenames to find everyone else who is there.
Using this technique, I've managed to find all the other people in the household with the same surname in every case. When they remove the mandatory restriction on surname later in the year (as they have said they will) then we'll be able to search for other people in the household.