Thank you for your replies, and yes sorry - I meant rows, not columns.
I tried opening the same epub in some other e-readers like Moon Reader, Cool Reader, FB Reader, Aldiko and each reader has its own quirkiness in rendering the same table. Moon Reader (although a great reader), for example, just completely ignores the table and clumps all the text together
Ah well, I guess I'll just have to live with this small annoyance for now. Converting the tables to images is tricky when porting on to different sized devices. Maybe future versions of the programs will better address this situation.
Cheers
n