I cured that fault, after also being frustrated, by removing both plugs from the mains (with the handsets sitting in the bases), waiting the obligatory x seconds (where x = 60, because I poured a stiff Glenmorangie Astar in the meantime) and then plugging the base phone back in, followed a few seconds later by the second unit. Lo and behold, the handsets connected !!
The original fault was caused by a power spike and outage - which seem to cause that fault every time.
We put the cure down to the Astar, so had a few more to celebrate ......
John P.
January 2012