I was reading your thread and I wondered if you had nay success in setting up a service. My son has just gained a place at SHSB and we are looking at moving to Southend longer term. However, that's not so easy at the moment and I woul prefer him to travel with other children rather than take the train alone.
Your post dosn't state from where your son will travel.
However, there is a school bus service that runs from Chafford Hundred to the school. There are a number of stops en-route and the service is available for both WestCliff Grammars as well as Southend Boys.
I'm sorry Fstray, as this service dosn't stretch as far as Ilford.
Although, on the plus side I do recall previous posts over the last 1 - 2 years for children travelling from Ilford/Barking areas - perhaps you can review the historic posts and get in touch with the relevant parents.