A little DIY
Our bath was out of comission until I rolled up my sleeves, headed to Woodies/B&Q and googled furiously. In the end, I just needed to re-seal the waste water fitting with some sealant. These websites came in handy:
http://www.practicaldiy.com/plumbing/bath_waste/bath_wastes.php and
http://www.victoriaplumb.com/bathroom_DIY/Fitting-a-bath.html
I did this a couple of months ago and still no leaks so happy days!