As for clients perceiving the social value offer negatively, we tend to find people choose us because of the way we share and distribute the surpluses we make. In honesty I've been working here a year and it hasn't come up.
Sometimes clients come to us because they know that we are the only place that would be interested in building what they are after. Amongst other things, basically, if we love a project and think it can help make the world a slightly better, fairer place, we may actually support it's development (or further development) by funding some of its design and build ourselves. That's one way that a client may get value, but not the only way.
In my experience engaging consultants, I've never asked how they spend their profits. It surprises me that would be your major selling point, but maybe your clients are spending other people's money.