Could you tell me what sort of battery the Holden Cruze takes? I have just replaced the battery with a DIN66. Is this the correct battery, as it takes a few seconds to kick over when cold? The battery guy is saying it's correct, but my mechanic said the battery is the starting problem.
Check the owner’s manual to find the correct battery for the car. If the replacement is the correct one, have the condition checked to make sure it’s up to spec. By doing those checks you should be able to eliminate the battery as the problem, or confirm the mechanic’s opinion.