Sorry, sorry, sorry - it IS essential to use stout champagne bottles if you are going to cork them.
I don't cork the demijohn, just leave the bubble trap in and usually friends and family demolish the lot pretty quickly.
I find that wine making is pretty easy but then I only use fruit (or parsnips) that I've grown and my criteria are low - taste and alcohol content - I don't expect it to taste like grape wine, just to taste nice. I try to get around 12% alcohol, and don't mind if it's not crystal clear, although it usually isn't bad.
If I do bottle the wine, I don't kill it with campden tablets (can't afford all that anyway) I just pour the lot into my preserving pan, cover it with tin foil (no lid) and bring it slowly up to pasteurising temperature, keeping it there for 5 minutes. This kills the yeast and stops any secondary fermentation and doesn't affect the alcohol content as long as you bring the heat up slowly and don't boil it.
Jenny