There are a lot of things to consider when you are choosing a domain name, each will have a different bearing on your choice. If you are in any doubt, call Goldhosts for some expert help.
Most people choose a domain name to match their business. For companies like Tesco or Sainsbury's, this is fine, for a small plumber or decorator, this is not always the best choice. If your business name is "Ashford Plumbing" then a good choice for you AshfordPlumbing.whatever, if you are A J Smith, then AJSmith.whatever will only help if people are looking for A J Smith, .
The type of domain you use should try to match your business area. If you are trying to sell to the whole world, then a .com is almost a must. If you are only selling to the UK, then a .co.uk is best. If you cannot get the .co.uk or .com that you want, then consider the other options like .net, .biz, .org, or even .eu. These however do not have the kudos of .co.uk or .com, and you may be driving traffic to your competitors, if your clients mis-remember your domain.
As of 2014 there are now a huge number of domains-extensions to choose from. These extra GLTD's should help the public understand website addresses better, and give the website owner a wider choice.
As I mentioned under business name, your key words should appear everywhere. That includes your domain name. when the search engines are trying to work out what your site is about, and they find the word plumber more often than any other word, they will guess your site is relevant to "plumber". This will increase the chances of you getting hits for that "search term".
If you are only interested in jobs in Ashford and the surrounding area, then try a name like "AshfordPlumbers.co.uk". Think of a search you have probably done...
"I need a plumber...",
Go to www.Google.co.uk (that IS how you find things these days...),
type in "Plumber"...
From this you will probably get a list of plumbers in Ohio! Doh! So you will probably change your "search terms" to "Plumbers Ashford". That IS locality, now you can see why the domain name AshfordPlumbers.co.uk would work so well.
Try searching for "Plumbers 01233". Then your results will ONLY include pages with phone numbers on, and they will be for the right Ashford - not Ashford Middlesex or Ashford Ohio!