You won't find Renardine in any garden centre as it has been banned and it is illegal to sell it or have it in your possession. Sorry but I don't agree that the ultrasonic repellers work either. I believe the best things to stop them are either strong smells or noise. Citronella is supposed to be quite effective, but obviously you would need to re-apply this after rain etc. I'm not sure if making up a solution using citronella oil and water and then sloshing this around the boundaries of the property would work, maybe introduce some windchimes or some other noise maker as well to double your chances of success. Human hair is also said to be a repellant, but I think you would need quite a bit to be effective and then it's not a particularly attractive garden mulch is it? Good luck