I remember reading the JRF report you've referenced when it came out. I felt it was rather anecdotal and, in any case, not really designed to answer the question I am looking at in this article.
Inside Housing had to cut down the article to fit the space; the longer version said -
"The point isn’t that [mixed communities] are necessarily bad – that would just be to swap one over-simplification for another. Social housing and social policy generally is a messy business and research can only suggest probabilities and possibilities. Better that however than leaving it all to economic imperatives and the false certainties of political rhetoric".
It also mentioned the work of Paul Cheshire and I would endorse Tom Chance's comments above - the report he provides a link to is an extremely well-researched (and nuanced) analysis. A much better read than my article for those with an interest in the subject.
Anyway, people can read both reports and make up their own minds.