And just looking at the first one on the list, the Paul Hamlin Foundation I see this about them:you must be confused with those Brexit think tanks funded by right wing libertarian groups
However the Migration observatory, is a trusted source.
here are the sponsors
Funders of the Migration Observatory
Based at the Centre on Migration, Policy and Society (COMPAS) at the University of Oxford, the Migration Observatory provides impartial, independent, authoritative, evidence-based analysis of data on migration and migrants in the UK to inform media, public and policy debates, and to generate...migrationobservatory.ox.ac.uk