I have recently seen MSFS 98 in a pack with something else - maybe Golf. You need 98 because the scenery won't work with anything later. I am not aware of any other product for the UK that provides continuous topographical coverage.
I believe you can still get the scenery. Perhaps you need to order it from <a href="http://www.vfrscenery.com" target="_blank">VFR Scenery</a>
It is rather similar to the in-built scenery but has accurate roads, railways, rivers, conurbations etc whereas the standard thing is only populated to any extent in certain places eg around London. It has lots of little airfields.
Fly along the coast and you get beaches and breaking waves. Go down to Lands End and you'll go over the China Clay quarries and so on.
The above site has downloadable lists of radio aids.
Naturally it has controlled airspace but of course, as in real life, it is just the colour of normal air...