i just got hold of the radiology reports
on 2nd july 2014 there was a 2mm diameter anastomotic defect associated with small posterior anastomotic leak at 5 o'clock with 1cm diameter track extending for 4cm anterior to sacrum, reaching S4/5 junction
on 8 september 2014 the mri showed the small posterior cavity has decreased markedly in size with only a tiny residual cavity (23 x 4mm) remaining although this still communicates with lumen.
i guess there is reason to be optimistic this thing will completly close up in the next few months?