I may just be being daft here but I'm not 100% sure my Advent 4211 is charging properly. I left it all day (about 6hrs) on AC power while I was away and when I came back the battery was at 55% and blinking amber.

I whipped the cord out and put it back in and the battery light is solid green again.

Am I right in thinking that flashing Amber is bad? If I'm reading the MSI manual correctly this indicates a duff battery?

Yes a flashing amber battery light probably means a problem with the battery.

Took the 4211 back to PC World today. The chap at Tech Guys who took a look was great and agreed almost immediately that it was porked and needed to be replaced.

I've got a brand new 4211 which seems to be working spot on.