A "quick and dirty" fix for this is to hard code the information into the file admin/view/template/sale/order_invoice.tpl as follows:
immediately before the last </div> line in the file (four lines from the bottom) insert a line reading
<small><?php echo "[xxx]"; ?></small>
where [xxx] is the company and VAT related disclosures you wish to have on the bottom of your invoices.
It may not be pretty but it costs nothing and it works.