Newbie query on repainting built-in shelves


I am fairly clueless in DIY matters but money is tight so here goes.
Ten years ago I bought a small terrace that has built in shelving either side of the chimney breast. The upper shelves are only deep enough for books but at hip level they stick out far enough to take a stereo or a small TV. It looks like a proper carpenter's job, d/k what the board / sheet material is made of, but the edges look decorative and seem to be made of machined wood.
The matt white varnish surfaces look very tired now and even abrasive cleaners can't get rid of some marks left by dried on cups etc. (Shouldn't have used abrasive clearners in the first place I hear you say ....)
Worse still, my stereo had an undetected puddle of dried juice underneath (I'm not a slob, honest, I blame it on the kids). When I yanked the stereo off its surface the other day it took large bits of paint off that had stuck to its feet. My wife still went at the surface with hot water and multi purpose cleaner which made the edges of the remaining paint work and the material underneath warp, so that the whole thing now looks vaguely like the surface of the moon. Some major surgery seems in order here ...
Even I have heard about sugar soap as one way of degreasing old paint surfaces, but would it not soak into the exposed fibrous bit and stop the new paint from sticking?
Also I could fill the holes with filler let it dry and varnish over it but would that give me a hard wearing surface? That stereo has to go back pretty much into the same position.
Or should I sand that whole surface down a bit and build up several layers of varnish? (Haven't got the tools.)
Lastly do people bother with primer nowadays, when some laquers claim that one coat gives you a decent result?
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In scribed for want of a better word:

<http://www.formica.co.uk/
Why not use a nice sheet of Formica, pre-cut to size drop it on an voila, and it will wipe clean for years and years and years
--
Clean round the Bend "Jimbo"

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