Atmasphere,
I've reattached the support base to the Mambo arm tower and then placed 5.5kg weight on that. I've kept the two (of the three)exposed spikes on the column and then drilled and tapped a 6mm hole at the end of the support base: so as to have a tripod of spikes that hold the whole thing about 3mm above the birch wall shelf. I've then rolled four small balls of blue tac and placed these under the four corners of the support base (the weights ensure that the blue tac is squashed firmly against the platform (or plinth!)and that the arrangement is grounded through the three spikes.
It's not the prettiest arrangement (given the old small bar bell weight that I have used on the arm tower/ supporting base) but it really works and is costless - until such time as I can obtain a more aesthetically pleasing arm tower.