When looking for a local tradesman you must learn to...
ask the smarter questions.
It can be so confusing trying to find a Fencer or a Drain company or a Double Glazing company just to mention a few. In Northampton Alone their are so many directories on the internet, with so many listings.
The best way by far to choose a reliable plumber, electrician or builder is by word of mouth. Ask family, neighbours, colleagues or nearby friends for referrals.
It's also worth asking industry contacts. For example, if you're looking for a reliable plumber and you've had a good experience with another professional, such as a roofer or an electrician, try asking them for a recommendation. Make sure you let the plumber know who referred you and they might even give you a discount.