"Stitches left in for six weeks"

I had a laparoscopy at Basingstoke hospital in July, and was told that the stitches would dissolve. I've never had stitches that dissolve, so when they were still there a few weeks later, I didn't question it. Six weeks after my laparoscopy, I went to an appointment at Winchester hospital, where I was due to have another laparoscopy in September. I mentioned that my stitches had not yet dissolved, and the nurse assessing me was shocked. She had a look and said they were not stitches that would dissolve, and should have been taken out within seven days of the surgery. She said I should have been given a letter explaining all this when I was discharged, and she apologised to me for Basingstoke hospital's mistake, even though it was clearly not her fault. She said I was extremely lucky I didn't have an infection,which would have prevented me having the second laparoscopy scheduled for the following week. I had them taken out by a doctor at Winchester hospital immediately. I have complained about this to Basingstoke hospital, but don't feel it is taking the matter very seriously, as it's been over three weeks and I still haven't had a response or apology.