g'day peter,
not sure what you may have over there but over here there is a product
called root barrier it is like rubber sheeting that the roots can't
penetrate. you can instal it yourself by digging a trench (hard yakka
doing all that digging) or have someone install it. can't see just
simply chopping the roots being a long term arrangement as like tree
branches that get pruned other roots will grow back and continue
spreading.
len
snipped
--
happy gardening
'it works for me it could work for you,'
"in the end ya' gotta do what ya' gotta do" but consider others and the environment
http://home.dnet.aunz.com/gardnlen/