Meanwhile back at the airport .......
Commercially I would offer a few comments. Firstly, about Olympic traffic. Do bear in mind that the Olympics are for two weeks. Making significant capital investments on the basis of traffic in this period is just inappropriate. You are OK if you are the Olympic Delivery Authority and can reach into public funds for whatever you want, and don't have to care whether it is wasted afterwards, but that doesn't apply to commercial investment.
Secondly, regarding the train service, it wil be 55 minutes to Liverpool Street, eight stops along the way, in a suburban-standard train which usually has many standing passengers in the morning approaching London, and leaving there in the evening. That's a long journey in such a train. It's not even the main railway from Southend to London (that goes to Fenchurch Street). Another 15 minutes is what it takes by train from London Euston to Birmingham Airport station, at the same frequency and in a proper long-distance train. Despite this, Birmingham airport has never made any headway at all in attracting passengers from Greater London.
Lastly Southend is in a poor geographical position, as it has no catchment area to the south or east, and because of inadequate access very little to the north as well. There is not a lot of commercial or industral activity in the town, which really functions as an extended commuter suburb for Greater London. The only way it got any traffic in times past was by handling overflow traffic from London, traffic which has now diverted for the business world to London City, and for low cost to Stansted.
This is why the once substantial traffic (well, in summer, it always fell right away in winter, and it was long, long ago) has been lost. Think Manston, in a very similar geographic position, they have had similar success, or lack of it, in attracting traffic.
Yes, it's OK for a jolly in my PA28, which gives a fine view of all the uninhabited Essex marshland that surrounds the town, and as a storage area for unwanted jets. But as a base for a significant commercial operation at adequate frequencies, I can't see where they will get the passengers from.