Just came back from London. The expo was nothing like I hoped it would be. There were just one consultancy from New Zealand ( the one advertised on their website), also there was one construction company, a couple of recruitment companies and Auckland Transport. I had the chance to meet a lady from the consultancy who kindly offered to forward my CV to people she knows and that was it.
As far as other companies and countries is concerned, there were some Canadian recruiters, Immigration consultants and international movers.
Overall there were about 20 exhibitors, I stayed there for about 2 hours including the time I spent waiting in queues.
Concluding, I don't think it is advisable for someone to travel from another country just for this event, but this is just my opinion.
For anyone thinking of going to future events like this one, make sure you have in advance as much information as possible and make sure you are there at least half an hour earlier to avoid big queues.