Hi Georgie
I also have an organised seroma/hematoma.  It came from my original surgery back on 22/12/11.  I have had doctors at the hospital try and aspirate it 3 times now with no luck.  Once was under ultrasound.  What they have been able to remove went to pathology and came back with no bacteria in it.  I also have a superficial infection for which I have taken numerous antibiotics but it is still there. That came from my second surgery or drain on 19/1/12  It worries me because I am having chemo (number 3 FEC coming up next week).  My white cell count is already low and I have had to have an injection to boost it.
I agree with you that it is annoying and I also want it gone but I am sick of the pricking, prodding and poking and they have now said they want to treat it conservatively and one if I get very sick from it will they look at surgery.  If I have surgery they will have to stop the chemo and that is not a path we want to go down if we can help it.
I will be interested to see what your doctor says and see how you go.
I wish you better luck than me :-)
Mich x