I've been thinking about all the oak beams, doors, etc. there must be in the UK which have never seen a finish of any sort - just sitting around developing patina. Lucky, lucky you.
Clean your panelling with methylated spirits (is that white spirit over there - it's the stuff alcoholics drink when they can't get cheap Australian wine) and 0000 grade steel wool. The metho won't raise the grain like water does and evaporates quickly.
Use a paint stripper on the painted edges (use a cheap artists brush to keep it confined to the right places), remove paint and clean off the residue with the steel wool and metho. If there are traces of paint in the grain, use a hard toothbrush at the paint stripper stage, scrubbing in the direction of the grain. For really hard to get out bits, use a needle - a wool needle (for sewing handknitted garments) has a rounded point. I've hot glued one into an empty ballpoint pen - easy to use and easy to find.
You will remove the dirt and gunk but not any patina that has built up. I recently stripped a Victorian mantlepiece of umpteen layers of paint, initially using a heat gun and then moving to paint stripper, metho and steel wool. It came up a treat.
Sanding sealer is optional - but it will fill the grain, if that's what you want. Finish off with two or three coats of a good traditional wax polish containing canuba wax for hardness, allowing two or days between each polish for finish to dry. Mylands (
http://www.mylands.com/) make an Antique Brown Wax suitable for oak. You will also find quite a bit of helpful restoration information on their site.