In reply to davenev:
I've taken part in this type of survey, and use the data routinely as part of my job (epidemiologist/academic).
A whole range of analysis can be done on this type of 'micro' survey data that benefits everyone.
As an example, my work involves developing better mathematical descriptions of social interactions and how society 'fits together'. We use this sort of information to make better predictive models of how things like pandemic flu will spread in the UK, and how best to tackle a pandemic before a vaccine is available (for e.g., where and when should we do school closures? ). My academic interest in the sort of household data that is collected only uses a small amount of the information collected (mostly how many people live together, and what sort of characteristics are there in the same household, such as age, sex and ethnicity) but is utterly crucial in getting the sums right. We can't infer this sort of information from other sources, despite what the enemies of the Census would have you believe.
Another example would be studies which can tell us whether a particular government initiative is working or how much it is harming people. They need this type of survey data, and to be as representative as possible. So even if you'e not affected by some of the issues for which questions have been designed to dig into, it's important to know what you think or experience to better represent the UK (or England, Scotland, etc, depending on your geographical bounding of choice).
So, your involvement is beneficial to a whole host of research that can be used to improve your communities welfare and health, even if your personal benefit seems intangible. Please do it, it is an important study and you will really be helping!
