What happens if the UK gets involved in WW1 on France's side, but only in a Naval/Air capacity? And does to France what the US did to us in WW2;forces France to pay in hard currency for the supplies and for blockading Germany under threat of pulling out of the war otherwise, bleeds France dry and in the end makes it sign over many of it's colonies to us?
I am taking this initially the BEF stays in the UK. The short answer is the CP win, probably in 1916, but it could be 1917.
Longer Answer: The BEF is about one army missing in 1914. Without the BEF into the gap at the Marne, the Germans likely hold the Marne. It is possible France pulls out forces from other locations and perform roughly the same as OTL. So Germany is somewhere between OTL lines and the Marne. It makes a lot of sense for France to abandon attacking into A-L, but this was a emotionally important decision, so it is hard to call. Germany halts due to logistics.
We then get to the race to the sea, baring the French lines collapse. France will have trouble getting enough forces to block Germany advance. IOTL, Ypres was a hard fought battle. Without the UK there and much lighter amounts of French forces trying to hold the GAP, the Germans do much better. The Germans might get as far as the Somme. Calais likely falls. Harcourt and Amiens are largely a given. Again, Germany has horrible logistics.
Nothing about this save A-H from Conrad, so the east is doing badly, and by May 1915, Germany will have to turn east. It likely sends more forces east, quicker than OTL.
So the question becomes, can Germany push from the Somme or Marne and take Paris between roughly December 1914 and April 1915. They likely try to and fail.
Now to what does the BEF do? Until the Ottomans enter the war, there are not a lot of good places to land. One can't rule out landing in Albania, but I don't think this is likely. If the Ottomans still enter the war roughly on time, then the Gallipoli type operation is likely. Or Gallipoli and Alexandrette. The Ottomans are hit harder and faster than OTL, but the attacks likely stall after making a good beachhead.
You call argue either way on Italy entering the war. If Italy does not enter, it becomes a very short war (1915 win for CP is possible). But let's assume about OTL entry date. This front should be much like OTL for 1915.
Falkenhayn will want to hit west, but will be force to go east. He will have more forces available. It goes as good or better than OTL. It also does not stop in August, but goes on until the heavy snows. The Germans likely make 150-200 miles farther east (4 or so more months advancing). Russia is in bad shape.
In 1916, you can write a lot of different TL based on assumptions and the details I have skipped over. Falkenhayn likely breaks France's will to fight this year, and we see peace talks sometime in 1917.