Battery going flat overnight

I have a 2009 Aveo and am having battery issues. I went out the other day and the battery was flat. Charged it enough to get it started and drove about 15 miles and shut it off. 2 hours later it was dead flat again. Jump started it and got it home and put it on a charger. Next day the charger showed full so I carried on. A couple of days later, flat again. I took the car to the battery shop I bought the battery at and they load tested it and said the battery was fine. Then they ran a battery diagnostic on the car and said it is charging fine. I put a volt meter on the cigarette lighter contacts and monitored it for a few days and it shows 14.57 volts anytime the motor is running. Battery kept dying so I pulled the battery cable off and inserted an ammeter. With the car off and doors closed it shows a drain of about 2 or 3 ma. Various combinations of dome lights, parking lights, radio etc. all show a draw of up to about 5 amps. Turned everything off and it went back to 2 ma in a couple of steps over about 30 seconds. If I put it on charge and bring it right up to full and then drive for an hour and put it back on the charger it shows well down. The charger only has 4 idiot lights to show charge state but it takes overnight at 1A charge rate to bring it up to showing full.

Any ideas?

Brian