Slow Windows Updates

Over the past year I have noticed that the Patch Tuesday updates are taking longer and longer. The majority of the desktops/laptops are Windows Se7en but the problem is there on Vista as well - no Windows 8 or 10 as yet. I have Googled the issue but the only suggestion is that it is due to the creation of the restore point. I feel that this is not the case as the download seems to be getting slower - download from other sites is fine. On the biggest sets of updates the download has actually dropped out and I have had to resort to doing the updates in two or three batches.Is there anything that I can change to improve things - nursemaiding PCs is not my idea of effective use of time! Thank you...