The relationships stated are (meant) to be in relation to the head of the household - so truth or not, this census says Ada is Allan's sister. And Dorothy is Allan's daughter (and so by default, assume Ada is Dorothy's Aunt.)
The ages are fine for Ada and Dorothy in comparison to Ada & Doris.
It's only Allan whose age is way overstated. But he has the right occupation
The enumerator may never have clapped eyes on "Alan" and so may never had the chance to wonder if he really was a young looking 50 yr old?
I guess they would not have known if they provided the truth in name and age for the Census, if it be tracked by the Police - so they fibbed.
Since the 1901 Canada Census indicated they all arrived together in 1901 and they don't seem toi be in Canada for the 1901 Census - I'm not surprised to find them (if it is them) all together in the 1901 UK Census, with enough details changed to disguise them.
The address seems to be a house in Brixton area of London - and they appear to be sharing the house, but occupying their own 2 rooms as a seperate family with a London born family named Evans who occupy the rest of the house (3 rooms). Mr Evans was a Tobacconist & Newsagent.
here are some photos of Acre Lane - one is circa 1900
http://www.urban75.org/brixton/history/acrelane.htmlCheers
AMBLY