He'll name a date which is probably too soon (they all seem to think that we have the luxury to travel internationally at the drop of a hat). In which case you can stall him off (make up stories about getting the passport, visa, etc.)untill I find another baiter, and see what days are best for them. Also ask him the address, exactly where, he wants this meeting to take place.
Dont give him a definitive date for your travel untill I can find a baiter in London who will agree to do this and on what days that baiter will be available.
No problem. I will use the excuse of the hurricane for a while, then go with the passport expired story.