Comments disappearing

Hi guys. I have a site running Revo 2.2.4.pl with several Articles running.
Comments are not appearing on about half of these and all the usual suspects have been checked

- Comments are set to 'on'
- Comments have been approved
- Ditto calls have been checked

Someone has had a look at it for me and thinks is a Quip to database issue and that Quip may be flooding the database with queries. This theory is based on the fact that when we set comment pagination to '1', comments display. Obviously, this is not ideal.

When we compare a Quip call that works with a Quip call with no comments, the calls are identical (apart from the &thread parameter).

Would anyone have any suggestions as to what my next steps should be?
Incidentally, importing this site into MODX cloud works and I can see all the comments but we have already paid for hosting.