Possible Clues:

• Sudden inspiration in bar, potentially?
• Session where an idea might strike like lightning!
• Participate in a think tank session
• B___ awful weather? Fancy, out of nowhere!
• Roman Brit's strange aberration
• Clever type from The Tempest will need to do this to arrive at 23 down
• Think British must get terrible weather
• Sudden inspiration in squall following bit of bother
• A follower gets to hold the crown, in a manner of speaking, from The Tempest offering to hold a group discussion
• Sudden clever idea