The answer is: British forces are unprepared for the war that may soon happen. On the other hand, the Czechoslovakia army force was prepared enough to serve and defend their country in the expected war.
Barlett beleived that the british army was too over-confident about their power since on paper Great Britain was ecnomically more succesful compared to the Czech, so they beleive that the difference in millitary weapons and supplies alone can make the Brtish Soldiers far more dominant. They were wrong.