I had an issue on my MGB GT many moons ago. I replaced the two six volt batteries, most of the ignition system. gave up and went to a 'specialist' garage who diagnosed and replaced the starter motor. It still wouldn't turn over when cold
I took the whole of the top end apart in frustration and found a slightly loose engine earth strap, so do check your engine earth strap is good. While you're at it, check your starter solenoid connections and the solenoid itself are OK and make sure the battery terminals are in good shape. It doesn't take much corrosion to stop 12v working. I'm sure other suggestions will arrive from more experienced members (since I have zero specific knowledge of the Ford Galaxy). Good luck.