Order of the Golden Sprout The New Robert Rankin Fan Club

Hi folks,
a work colleague of mine is trying to track down a book but can't remember what it's called. Can anyone identidy it from his description?
 
The plot is that the sun (not ours it transpires) starts showing signs of iron in its spectrum which predicts that the sun is about to go Nova.  The scientists construct a fleet of spacecraft to escape.  Only a limited number can go on the ships so the ships have to be protected and trouble starts to erupt in the population.  Eventually the ships lift off.  One is damaged during the escape and eventually is blown up by one of it’s surviving officers (as conditions on the ship are deteriorating towards anarchy).  The fleet leave the planet and eventually the star goes Nova.  As they flee, the ships are gradually being separated from each other.  The outermost ships begin to stop contacting the central ships.  Some of the staff on one central ship deduce that this is as a result of the escape craft gradually being picked off by Aliens as they head towards the presumably highly populated Galactic Centre.  They turn around and head out along one of the Galactic arms, eventually encountering and landing on (our) Earth
 
Thanks