Your first port of call is likly to be a directory such as Yellow pages or Thomson. This is a good start but reputation is also key to choosing the correct pest professional. Also searching your area in google or bing will provide you with Pest controllers in you area. Remember bigger is not always bette
Professional Pest controllers are trained to high standards and have many years of experience dealing with pest species. Different pests do require different treatments and different formulations of chemicals.
Ask your friends and family for recommendations. Ask if they were happy with the result of the company that carried out the treatment.
Ask what pests were treated and if they eliminated the pest. Also to ask you family and friends as to why they liked or disliked the company and if the rate charged was reasonable.
Most good pest control companies will offer a free identification service and quote you a price after identification to eradicate the pest. They will also provide a report to advise on the pest type, the location of the pest and the proposed treatment. They will also carry out a risk assessment, this is especially important if you have pets and children as certain chemicals can affect cats and other non target species.
There are companies in the UK who act as call centres and outsource their work to local pest control companies, this increases the price and you are not dealing directly with the pest control business. Also make sure the company has insurance to carry out the work and is qualified to carry this work out. Remember Rodenticides and Pest control chemicals are dangerous in the wrong hands of an untrained professional.