Unfortunately, having been a Trustee of three different charities, I've learnt that any charity or other organisation that's responsible for serving the totality of a particular population has to do much more than just "live and let live": the reality is that white, 'middle class' people will access any service much more easily than anyone else. That's because such people (and I include myself in that) have multiple privileges, such as time, confidence and literacy and assertiveness skills - and not having to battle the systemic racism that 'white-led' organisations tend to have.
As evidence of this, I bet that the proportion of white, middle class people who access this forum is much higher than the proportion of white middle class people in the total UK population of diabetics. As with any charity, Diabetes UK has a legal responsibility to find ways to support 'harder to reach' populations. It may be doing that very well already but it can never be complacent.
I spent most of my career working in the NHS in London and in the West Midlands and I had to work constantly to make the services for which I was responsible as accessible as possible for the wide range of different people living in the catchment areas. For example, don't rely only on sending appointment letters through the post to traveller communities - and take Ramadan seriously when it falls in the summer, in terms of appointment times.