walls.? The house was extended approx. 15 yrs ago and the palm tree sits at the side of the extension of the house. Can anyone tell me if this will affect the water table, potential damage that the roots can cause to the house, any problems if we are to remove it?

Living in australia, can we sell it and is it worth anything!!

Not sure about it's worth. A good size tree here (USA), about 6' tall goes anywhere from $30 - $100 depending on the tree and where you get it from. However, if you are not careful digging it up, it could go into shock and die. I plant lots of trees at my house and they are not cheap. I have one that is hell bent on attaching itself to my propane tank. I've dug it up and it leaves seeds that just grow back. If the extension has no water pipes under the ground, then it should be ok.

Palm trees tend to have shallow roots, They are accustomed to dry/sandy soils where there subterranean water table is either brackish or too deep to tap, so it's roots wander out to maximize catching any surface moisture. You should see the roots if they are moving towrd the the foundation. If keep the tree watered it will pose no problem as it does not have deep roots to dry out and compact the soil under the house. A mature tree can always be worth money if someone wnats a mature tree and it is not a very common species.