Workaround to batch map image problem

QGIS 2.6 (Brighton) handles map refreshes completely differently to QGIS
2.0 (Dufor) on which development took place. It seems to be a step
backwards - there's les control over the map refresh. The problem is
that it stops the automatic batch image generation of distribution maps.
I've put in something of a workaround, but it is much slower than
before.