Member Since: 4th Feb 2016
8th Aug 2018
From the tone and content of your enquiry, I get the impression that "cloud-based" is your most important criterion. (If not "most", then certainly up near the top).
I would therefore recommend that you take a look at Aqilla. This was designed and built, from scratch, to be cloud-based. It is not a "non-cloud" system that has been belatedly shoe-horned into the cloud.
I also believe that they have numerous Charity clients (also see the other respondent in this thread).