M8, it's a HUGE field to simply jump into and spend your money. Pretty much no different than saying "I want a car for £500" without any preferences other than getting from A-to-B.
For £500, you won't be able to see a massive difference in the stars. All you'll notice is that there are more of them through the scope - but ultimately, they are still flickering points of light.
By far a better option (and within your budget) is to go in search of planetary astronomy - including the Moon. Even with an entry-level scope, the Moon is much more impressive to see. Ridges, craters, seas (in the naming sense) are much clearer to view. I did this thread with a few shots of the Moon back in 2008...
http://www.cliosport.net/forum/showthread.php?t=372700&highlight=moon
There are other factors to consider as well. Do you have a lot of light pollution near where you are? Would you have a stable platform on which to place the scope itself? When looking at extreme distances, even things like your own heartbeat can make the viewing image jump and move - such is the hyper-sensitivity of the equipment. It's quite common for amateur astronomers to have a concrete base in their garden on which to place the telescope. Much better than either on decking or a lawn, etc.
Astro photography is another common feature that people get into - but again, you're looking a time-lapse cameras, camera mounts and a scope that can track the night-sky. Quite technical, but some of the results achieved with it are simply amazing.
My best suggestion to you initially, is to meet up with a local astronomical society - a search on Google should do the trick. They aren't all geeks who can quote Star Trek episodes verbatim from 1973
- and most are just enthusiasts who like to look up at stars. Most places welcome anyone (joining as a member not being required) and at least that way you will get to have first hand experience of scope kit and what's involved in setting them up. Not forgetting the knowledge of the people who use them.
D.