Novice with aching hands I'll be interested to hear what the experts say, but there are a couple of problems with left-handed ringing. First, when ringing up and ringing down the rope has a right-hand lay and will naturally form loops when passed from the right to the left hand. This is not co-incidence, sailors regularly coil ropes and the ropes are made to make this task easy. The other problem is that if the ropes fall next to each other, a left-handed ringer is likely to throw his rope out the other way, and there is the risk of entanglement or grasping the wrong rope.
"Tutors Handbook" CCCBR, ISBN 0-900271-36-1 p17
"The New Ringer's Book" CCCBR, ISBN 978-0-900271-93-9 p7
Coleman, Steve: "The Bellringer's Bedside Companion" Sue Coleman Publishing, ISBN 0-9523896-0-6 pp306-317