tbh, i don't have no specific experience of the previous shape galaxy regarding battery drain. However, if it was mine i would be checking the 109 relay in the fusebox. & also check the battery fuse box as i've seen a few of these totally knackered due to water ingress. &

109 relay is the one that powers up the ecu and prone to problems, although i dont remember battery drain being one of them. Also are you sure 0.25a is ok? normally i'd be concerned with anything over 0.1A as typically you'd expect to see approx 0.05A after about an hour with a ampmeter in series.