I thought that it would work as a series of windows, framed by black machine spun wool flecked with a little white and with a purple sheen. (This isn't really evident in the photograph, however I'm sure it makes a difference in terns of the depth of colour in the finished piece.)
I'm very pleased with the final result and am going to think about how to get the contrast between my dodgy handspun and machine made yarn to work in future projects.