What conflicts? De Gaulle's repeated vetoing of British membership into inter-European groups? Quebec? The French declaring war on Britain during WWII without the Germans asking? The French attempt to invade the Channel Islands during D-Day when the Anglo-Americans were in Normandy?The Franch / English detente started because of Germany, both were worried about what it intended to do.
The quick way to stop the "friendship" is to stop Edward VII promoting the entent cordial, as I think this was almost a single handed effort by him to promote friendship between the two countries.
Given the conflicts between France and Britian since WWI I think it would be easy to have a Cold War between them (indeed I know people in England who think there is ALREADY a Cold War!).
More liberal Germany along the lines of what Victoria and Albert wanted, maybe. Have them retain closer connections to Hanover and Saxe-Coburg. Then have the French manage in their attempts to get Luxembourg, the Bavarian Palatine, parts of the Prussian Rhineland, at least half of Belgium (being the part with all the industry but no ports), and maybe the northern section of Spanish Morocco so that they have ports near the Strait of Gibraltar. Then have a successful French puppetized Mexico having trouble with British Honduras, Canada goes for the French islands off their coast and takes away French rights on the fishing grounds, do stuff with Siam, a more aggressive Russia close with France...Have the Fashoda Crisis blow up into a war (which would have been short, mostly naval, and ended with a British victory). Or have one of the many efforts to achieve an Anglo-German alliance in the late 19th and early 20th Centuries succeed.
Why did England and France go from being long term enemies in the 19th Cen to being allies in the 20th? Can you come up with a TL where they are still in at least a Cold War as of today?
What makes you think we've stopped being enemies? A MORT LA REINE!
Au trente et un de mois d'août...funny how thats still part of our drinking songs to.