Update...
The plum cider (plider as i have christened it) went crazy theother night and and is still bubbling away today. It is a fantastic red-orange colour, looks like fanta fruit twist!
Today i finished off the last of the plums. I used 2KG to make some jam! Yes JJSH i noticed just how much pectin they have in them, the jam is very well set and tastes great! I also attempted a plum marinade but unfortunately the results were disappointing, i think i made it too sweet, it just ended up tasting like spicy garlic jam, a very strange flavour

. Ha
I added a teaspoon of pectolase to each dj of the plum cider, should i add some more? It is currently cloudy in the dj's but i think a lot of that is the yeast and sediment.
I have also started a plum wine. I added 6bls of plums, two pints of boiling water and a campden tablet to a fermentation bucket. Will continue from there tomorrow.
I got the plums outside someones house at the side of the road, they had picked them and were giving them away for free! They have even more there now, but i think i have made enough plum based stuff for a good while.
Little story and a bit of a warning...
I had my plums siting in the fermentation bin, ready for me to add the campden tablets to them, as i opened the container of the tablets a puff of dust hit me right in the face and in surprise i inhaled it. It was bloody horrible and i felt it sting my throat. I instantly started coughing right from the depths of my chest and did not stop for a good 5+ minutes. I checked the ingredients on the campden tablets and gave them a google search.
They are.
http://en.wikipedia.org/wiki/Sodium_metabisulfite
http://en.wikipedia.org/wiki/Polyethylene_glycol
Luckily i found out they are both non toxic and can easily be broken down by the human body. However Sodium Metabisulfite can cause reactions to asthmatics, so that explains my coughing fit. On a lighter more funny note Polyethylene_glycol is used as a laxative.
I think the reason why the dust was in there is that they had not been used in almost a year, but the box containing all my home-brew equipment had been moved around on multiple occasions so the tablets must of knocked about and broken up a bit.