Ray Saintonge said:
Correct me if I'm wrong on this, but I thought that Wohlmann was a UK resident.
He lives in Southern California.
Defaulting would not be a preferred option, but that too would depend on just what he is asking. Assuming that the defendant is a US person, he too should be able to receive an award of costs including travel costs. Perhaps he could be asked to pay conduct money or post a bond for costs of attending. It would be refundable to him if he wins the case.
I'm not in charge of the British legal system, so I have no authority to mandate any of the above.