Bump!* This is rapidly approaching and is not, in my view, to be missed. Jan an I are already booked in.
North Fambridge is probably the closest station, but there's not much in it. Witham is marginally further away and is served by more trains. Both are accessible form Lpoo St.
*I use this expression guardedly. Last year's event was almost exactly 9 months before this year's, and Clarion and Butterfly were there.