Importance of features in descending order are:
Aperture is probably the most important consideration when buying a telescope. Aperture is the telescope's ability to collect light as directly related to the size (diameter) of the objective lens or primary mirror. Generally, the bigger the lens or mirror, the more light the telescope collects and brings to focus, and the brighter the final image.
Focal Length, which is the distance required by the objective lens or primary mirror to bring all of the light collected to one point. Generally, long focal length telescopes are capable of delivering higher magnifications than short focal lengths. Focal length is expressed in "f" numbers. One site suggests f/10 or higher - good for observing the moon, planets and double stars (high power)
f/8 - good for all-around viewing
f/6 or lower - good for viewing deep-sky objects (low power)
Magnification Closely related to focal length, it's probably the most misleading denominator in purchasing a good quality device. As the magnification of an image increases, the field of view and the brightness of the image decreases. Almost all astronomical objects are best viewed on a low magnification or power to gather the most light possible.
Resolution is the ability to see fine detail in an image of the moon, a planet or a double star and depends upon how well the telescope can separate, or resolve, two close objects. It, too, is closely related to the aperture and focal length described above.
There are other considerations, but these, in my experience are probably the most important. (I'm in the U.S., so I can't help you with where to shop).
Best of luck and enjoy!