Attributing all this to intelligence sharing alone seems an oversimplification. I suspect the difference in the level of assimilation between British Muslims and their French counterparts is the biggest factor.
France has managed to avoid most islamic extremists by working closely with local mosques; by not treating them as the enemy but as a local resource. The extremists are spreading their views through the internet. They are not welcome in the mosque.
Yet any extremist can literally walk into France and terrorize, which is essentially what's happened.
So perhaps the biggest difference the fact that Britain has a physical border wall?
Statistically speaking, the fewer terrorists you allow into your country, combined with the fewer amounts of terrorist organizations you allow to operate in your country, the fewer terrorist attacks you will have.
Niqaab/burka != terrorist
The UK has decided that freedom of religion, no matter how intolerant it actually is, is to be protected. Even if it denies some human rights. France has decided that freedom of religion cannot supersede human rights, ever.
I think outlawing religious dress or other iconography simply ends up giving ammunition to religious extremists and further divides already segregated communities from the mainstream.
− la Direction générale de la sécurité intérieure (DGSI) − la Direction générale de la sécurité extérieure (DGSE) − le Service central du renseignement territorial (SCRT) − la Sous-direction de l’anticipation opérationnelle de la gendarmerie nationale (SDAO) − la Direction du renseignement militaire (DRM) − la Direction de la protection et de la sécurité de la Défense (DPSD) − la Direction du renseignement de la préfecture de police de Paris (DRPP) − la Direction nationale du renseignement et des enquêtes douanières (DNRED) − le Traitement du renseignement et action contre les circuits financiers clandestins (Tracfin)
And the coordination services: − l’Unité de coordination de la lutte antiterroriste (UCLAT) qui n’a autorité que sur les services relevant de la police nationale − l’État-major opérationnel de prévention du terrorisme (EMOPT) directement rattaché au ministre de l’Intérieur − le Coordonnateur national du renseignement auprès du Président de la République
A 2000 pages and 6 months enquirie by a bipartisan commission found we should unify them but it was promptly ignored by the government.
You're saying like this is part of the solution, but it's part of the problem
Though it seems that some of those still might make sense as a separate entity, like Tracfin and DNRED