The call-in answer phone system wasn't working from just after 6pm til 10:25 Sunday. I'm not completely sure what happened but I'm willing to blame John's cat - who may have walked over the computer keyboard and put the laptop into hybernation.
Or the cheap hardware and/or software I'm using fell over.
Either way I'm going to come and reset the system once a day - which should fix the problem.
Sorry to the riders who tried to call in during the outage.