Can you explain your situation a little more?
There isn't a basis for disputing the jurisdiction. A court outside London does have jurisdiction over London as it is within the jurisdiction.
Normally claims are designated to the local court of the claimant unless the claimant is a business.
Can I clarify anything for you?
Since you are both business it would probably normally be moved to her local courts.
Yes, if there is a trial then you would need to attend.
There is an application you can make to retain the matter at your local court but it is not likely to succeed I'm afraid
It depends on the nature of the complaint?
Only if they can show that you have behaved vexatiously or unreasonably.
Costs orders are rare at the small claims court and anyway usually there are no costs incurred.
All the best.