Because of internal problems, the UK doesn't send the BEF as OTL (or perhaps only a token force).
British troops don't arrive until early 1915.
Germany gets much further into France than OTL as a consequence, probably still going through Belgium, and perhaps takes Paris.
France sues for peace leading to crippling financial settlement and loss of territory, forced reduction in army and navy. War over by say early 1916.
Germany can turn East towards Russia with more force.
Consequences:
US never enters war and remains isolationist at least towards Europe.
France is antagonistic towards UK, blaming them for outcome.
What else?
Is there likely to be an earlier revolution in Russia with a more active Eastern Front?
Germany had its problems towards the end of the war and was near revolution itself. Could that be averted or would a bitter war in Russia still be a trigger?
If France makes peace how would Britain react? Would we make a truce or keep fighting? I can't see how, other than a blockade.
What would happen in Belgium? Would it remain occupied? What about Netherlands - or Denmark?
Focusing on Britain an early end to the war means less involvement also of Empire Troops. What would be the consequences if any?