S3 Starter troubles

Help! After fitting a new alternator and carb my landy won't turnover. I have also fitted a new battery. All I get is the clunk of strarter solenoid, however if I connect a jump lead from the -ve terminal to the block or starter itself the it will turn about one revolution then stop! The battery is new and charged, the earth straps are fine to! It also happens when trying to jump start it. Anyone got any ideas?? Many thanks.

Just read about codbasher's alternator probs - my charge light was on before I changed the alternator - are there any other earth points that might be dodgy - I have checked the one between the starter and chassis and its fine.