Having had to deal with people that fill in "which?" surveys, they generally say more about the person completing the survey than the subject of it.
I suspect the respondents are setting alarm clocks for them to carry out speedtests and interrogate their Samknows results down to the minute....
Don't get me wrong, I'm not saying the sentiment of the results is wrong, rather these are probably results from career survey completers - and given the size of the market, a fairly small sample too.
Which? Has also gradually moved from 'consumers champion' to a marketing company, carrying out carefully crafted surveys 'on behalf of' anyone that wants to wave some cash in their direction.