Have you got any facilities for making compost? I'm a fan of no-dig gardening and I spread any compost I can make on the beds each autumn. I have used well rotted cow muck in the past, but getting it delivered without having to barrow it to the plot is out, so I used shop bought compost and spread that. It works fine, but costs a bit more. Mumofstig is right - don't get too hung up on it, just do what you can.