I'm not sure of the current dollars-to-pounds conversion rate, nor do I know of any import taxes to the UK, but I'll do the best I can from this side of the pond.
The best "bang for the buck" deal, though not necessarily the best all-around choice, is a Dobsonian-mounted Newtonian reflector, often called "Dob" for short. This gives a very stable mounting, but no computerized abilities or motor drive at all--your brain is the computer, your hand the motor. The money is spent on optics, and there are no circuits that can fry, no batteries to die, and no motor or gear system to jam. The Orion SkyQuest XT 8-inch scope sells for $449 in the US. See their web site at Telescope.com .
For a decent entry-level scope with computer and motor, consider the Meade LXD55 line--there are several to choose from, so one should fit your budget. If you can afford it, consider the 8-inch Schmidt-Cassegrain version, or the 8-inch Schmidt-Newtonian. It comes either with computer (Autostar) or with just a motor controlled by an "electronic controller"--the Autostar will send the scope to any of several thousand objects stored in its memory, whereas the electronic controller just sends the scope up, down, left, or right at the punch of a button. See descriptions of this line (and others) at astronomics.com , the web site of a mail order dealer who has treated me well.
I'm not sure what mail order shops operate in the UK. A trip to the local book/magazine shop to find a magazine on astronomy published in the UK should pay off, since the advertisements in it may tell you who ships to your neck of the woods.
Avoid any scope that has 0.965-inch eyepieces. A scope with 1.25 or 2-inch eyepieces will allow you to upgrade the eyepieces as time passes. Remember, the eyepiece is half the optics. You can get a good Plossl for $50 to $100, or you can spend $250 to $600 on some of TeleVue's wonderful creations. But most people don't want to spend more on their eyepieces than they did on the scope itself. Most new scopes of any quality come with one or two decent Plossls, and you can live with those forever if need be.