In the Society's own words:
The St Barnabas Society, a registered charity, operates in Great Britain and Ireland and exists to provide pastoral and financial help on behalf of the whole Catholic community to former clergy ministers and religious from other churches, who live in Great Britain and Ireland, and who have been led by faith and conscience to come into full communion with the Catholic Church.
The website provides a link for online donations for this most worthwhile cause. I should mention that the introductory text is slightly confusing. It refers to making an online payment “to your parish”, but if you click on the link you will see that in fact the payment goes direct to the St Barnabas Society.