Just back from the sunny south of France. Delighted to be back obviously 
. Fabulous time, slightly marred by the incontinent birds lurking in the trees above our pitch. Our beautiful pristine bell tent (along with a tarp and DD's play tent) is now smeared in purple poo (berry-loving birds apparently). Any ideas for removing it without ruining the canvas? We had a couple of downpours there which don't seem to have improved matters greatly.