By Ron Bousso and Shadia Nasralla LONDON (Reuters) -Shell on Friday released an amended plan for the development of a major North Sea gas field which British regulators initially rejected last year on environmental grounds. Shell said in the new environmental development plan of the Jackdaw field that it aims to start production from the field, which will supply 6.5% of Britain’s gas output, by Q3 or Q4 2025. The British government has in recent weeks urged North Sea producers to ramp up oil and gas output as Europe tries to reduce its reliance on energy from Russia, following its invasion of …