Richard Wright wrote:
I am in my
fifth year of trying to get rid of it. Fortunately the heart shaped
leaves are readily seen when the vine pushes up to 50 cms or so. Must
catch them early before the aerial tubers grow, fall and contaminate
the ground all over again.

Learn to recognise the shoots and follow them down and dig out the roots
& tubers in the ground, It is the only way. They are still like potatoes
in that if you miss the smallest bit (pinhead?), it grows again.