By popular demand here's the recipe for my porter and stout that I mentioned here.
The malt grist was:
6kg Pale malt (Maris otter)
500g Crystal malt
500g Wheat malt
250g Chocolate malt
A portion of the strong wort was then boiled with 15g of Goldings hops at the start of the boil and 10g added ten minutes from the end to make my stout. I also added 50g of black malt to this towards the end of the boil.
The rest of the wort were used to make the porter and this was hopped with 90g of Goldings at the start of the boil and 29g ten minutes from the end.
The yeast was Safale 04.
I ended up with five litres of the stout at an original gravity 1.090 and 23 litres of porter at 1.048.
I've only recently started parti-gyling my brews to get two different beers and I'm really pleased with the results. I get to make something strong and/or weird at the same time as making a batch of something more drinkable.