There is a growing interest in HCI research studying technology for citizen engagement in civic issues. We are now seeing issues around technologies for empowerment and participation, long discussed in HCI literature, appropriated and formalised in government legislation. In the UK, recent reforms stipulate that community-based service information should be published in continuously updated, collaboratively designed and maintained, online platforms. We report on a qualitative study where we worked with stakeholders involved in the collaborative design, development and implementation of such a platform. Our findings highlight tensions between the grassroots desire to innovate and local governments' rigid compliance with statutory obligation. We pose a series of challenges and opportunities for HCI researchers engaged in the design of civic technologies to consider going forward, addressing issues of engagement in policy, measures of participation and tools for enabling participatory processes in public institutions.