I've got the same fault as above on my creda aqua chrome shower model no. 53-558205
I've had my shower since dec 2004, noticed a few weeks ago when I switched it off after around 10 seconds I would get a bubbling/boiling sound then hot steam coming out of the shower head, not good, thought the cutout sensor or pressure switch was failing but could not test
Found an exact replacement from Tesco Direct, £125 so if the PCB is faulty then replacing the shower is probably best value for money
maximilliontrouserpress, December 2009