hi Bear
thanks anyway for any kind of support: you guys did a very good job and gave it us for free, so anything else you can do on top of that to help us is always very welcomed!
the bug has gone from the live site, but it's still visible on the development one.
the difference between the two is that i've applied some upgrades to the core Joomla on the live one, hence it must be something to do with the Ja Purity template, which is the base used for the customisation.
possibly it's down to the module.php include that renders the side modules.
no copy'n'paste from Word has been made, i simply hate the program and i'm very aware of the amount of hidden crap it can throw in html code, so i just steer far away from it and the likes (i'm an oldskool fart and prefer handling my code by hand).
if it can be of any help, i'm attaching another couple of screenshots, one from the live site and another from the dev one, taken using FireFox with FireBug analising the snippet of code: