Besides the rough idea I get from the Wikipedia pages. Though I'm confused as to why it says the UK supported Poland during Zaolzie annexation but then says they were accused (never said by who) of being accomplices of Germany in annexing Czechoslovakia.
but then says they were accused (never said by who) of being accomplices of Germany in annexing Czechoslovakia.
By Soviet Union. After all Czechoslovakia was Soviet's military ally.
Mutual distrust and Munich were the main reasons negotiations between UK, France and USSR in 1939 about military alliance failed.
Also to answer to your main question, I can refer to Churchill:
"‘And now, when every one of these aids and advantages has been squandered and thrown away, Great Britain advances, leading France by the hand, to guarantee the integrity of Poland – of that very Poland which with hyena appetite had only six months before joined in the pillage and destruction of the Czechoslovak State."