Let me propose to you a scenario.
It's the start of the Twentieth Century and Britain fights the Second Boer War, which goes slightly better (insert previous POD which isn't important ATM). As a consequence the British confidence in her own ability isn't quite as strongly shattered- and maintains her splendid isolation.
So we're talking no Entente-cordiale or Anglo-Japanese treaty. Instead Britain plays the Germans and French against each other, by threatening both sides with taking the other's side. Now minimize the butterflies and fast forward 15 years to the start of WWI (yeah I know things are different but the cause could be anything, both were itching for a fight).
So Britain remains aloft as France and Germany pound each other on the Western front. Would Britain not sell to both sides and take out loans with both sides? Imagine the boost to Britain's manufacturing industry! The Government could put in that much needed investment and upgrade the equipment.
Rather than the decaying industry of OTL, and putting themselves into extensive debt; they could give themselves a head start and stabilise their finances long term. Whoever wins, they will be in serious debt and suffering the effects of a long term war of attrition.
What do you think? Am I right; would Britain have being far better off out of it? Or is the power of one nation receives by dominating the continent more than any advantage Britain could receive?