Are your upvc door or window locks becoming stiff or loose? They may only need adjusting or realigning. However, this could also be a sign that the lock mechanism is close to failing. It is advisable to get them replaced sooner rather than later as they may eventually fail in the locked position. This not only makes life difficult for you but makes the repair much more difficult and expensive. At northants lock services we specialise in all aspects of double glazing repairs, from locks, handles and hinges, to replacing broken or misted up glazing.