Sorry to hear you didn't make it but not being a UK citizen definitely was not the reason that you didn't get it. Loads of non UK citizens in BA, both from previous recruitment campaigns and this one.
Getting into BA isn't about how many hours you've got, it's about being the right type of person who fits their mould of the 'model British Airways pilot'.
Hence why the 4 short essay questions in the stage 1 application are so important.