Thanks JN114. I do appreciate your responses even though as a service user it is very frustrating!
Am i right in thinking that since the 387's are running all day HC are unable to turn at Hayes anymore? If so that just exacerbates the problem.
That exact scenario was looked at in the contingency plan review. Connect can run to Hayes bay with a full Electrostar service running - HC Unit and Driver need to step up one diagram to make it a 10 minute turnaround (so 2T18 becomes 2Y16, rather than 2Y18 it would form at the Airport) and that gives you a just-about working 4tph service in and out the bay. Heathrow aren't particularly keen on it, as apparently it doesn't really work with their driver diagramming, but I don't know any more on that.
However, if there's any subsequent limitation in capacity on the Relief lines between Hayes and Paddington will see the Connect service suspended to give priority to the higher capacity 387s, as it only works of everything is running on time. If Connect are suspended Hanwell is to be served 1tph with a Turbo, to mitigate risk of 387 calling outside of daylight hours. Hopefully can all be sorted out properly once Hanwell get some decent lighting.