Welcome Phill. While your lathe is a little on the small side, I don't doubt that you could turn a mean pen on it. You don't need much equipment to start, just buy a few slimline pen kits to practice with. Trawl our forum as well as IAP's IAP Home. Membership is free and they are loaded with grat tutorials for beginners and experienced folk alike.
The preferred mandrel here seems to be the Planet/Rotur one - don't waste your money on the £60+ one with the extras, just get the mandrel for £20 or thereabouts.
Have fun, and be aware that it is addictive!
