Sorry, not wanting to sound thick, but could you explain what you mean by access points in this context? As far as I know the crossover at Teignmouth is at the Newton Abbot end of the station at the end of the bi-di section of the up main, so trains would simply terminate at Teignmouth in the up platform and go back. I could see this being a problem at Dawlish Warren because it would mean trains going towards the worksite, but even here I would have thought there would be a way of getting round it by SLW or some such. If trains ran to Dawlish Warren with the stopping RRBs terminating there it would significantly improve journey times for commuters from Teignmouth and Dawlish into Exeter because in the peak the traffic in the Marsh Barton area is horrendous.
I'm still not sure how the breach has affected the signalling however, someone told me yesterday the signals at Dawlish Warren were all "black".