Add about 4 litres of water to your largest pan.
Roughly chop your bananas (including the skin) and add to the pan, along with the sultanas.
Slowly bring the pan to the boil, once boiling, turn it down and let it simmer.
While the pan is simmering, boil the kettle and add the teabag to a mug of boiling water and leave to brew.
Extract the juice from you lemon and add it to the pan.
Once the bananas and Sultans have been simmering for about 5 minutes you can start using the masher to gently mash the ingredients in the water, this will help the juices infuse with the water. Continue doing this until you can no longer feel any chunks in the water, this should take about 5 minutes or so depending on the size of your chunks. (Be careful with this step, the water is boiling and over enthusiastic mashing will cause splashes of hot liquid!)
Remove the teabag from the mug and add it to the pan, and give it a quick stir, this will add tannin which helps to give body and a balanced flavour to the wine.
Turn off the heat from the saucepan, put a lid over the pan (or tea towel) and leave the the liquid to cool a little. (If you have plenty of time you could leave this overnight, helping it to develop a stronger flavour.)
Once the liquid has cooled for a few minutes you can start filtering it into a clean saucepan using the sieve, muslin and ladle. (Be careful not to squash the juice through the cloth, this will cause unwanted particles to be pushed through and take much longer for your wine to clear.)
Once all of the liquid has been strained from the pulp you can add the liquid back into the original (cleaned) pan.
Bring the liquid back to the boil quickly, then carefully add the sugar to the pan while gently stirring it. Once the sugar has dissolved you can turn the heat off. This process just ensures that that all liquid is completely sterile when going into your Demijohn.
If your saucepan has a lid, put it on and leave the pan to cool for about an hour, if it doesn't you can cool the pan down in a a sink full of cold water.
Once the liquid has cooled enough for you to able to easily handle it without gloves, you can add the liquid to you Demijohn using your sterilised funnel. Once filled put your sterilised Airlock on straight away. (Don't try and add boiling water to the Demijohn as this can cause it to smash.)
If you are using Pectolase you can add this now. (Pectolase will help your wine clear slightly quicker, I don't find any real benefit from using it personally)
Add the yeast, use the quantity stated on the packaging.
Now your wine can start fermenting! For best results keep it in a warm dark place without fluctuating temperatures like an airing cupboard.