Hansard had some interesting figures last month showing the percentage of children from ethnic minorities in all schools and in Catholic Schools.
All minority ethnics: 27% (catholic). 22.5% (all state schools)
Black 7.9 v 4.6%
Mixed Race: 4.7 v. 3.7%
White: 80.0 v 80.6%
Slightly fewer children from Asian background in Catholic schools but these figures seem to dispel the myth on MN that Catholic schools are not good for community cohesion.