The mention of the cancelled shows is only part of it.... the events organisers have changed ownership and the characters actually doing the job have changed almosts annually. Lots of blood letting in this market. You may recall the Helicopter Show that did not happen at Silverstone... the characters involved in that were once part of Helitech and it was the new/current Helitech that was at the centre of getting the Silverstone event crippled......
Watch your back seems to be the pattern here!
If they did decide to go to ExCeL there may be plenty waiting in the wings to spread the acid and repay past 'favours'.....