Just finished my last kit (Woodfords Nelson's Revenge) & whilst pottering around my local homebrew shop, Harris's (those of Harris filter fame), I picked up one of their own brand dry kits for £8.
The kit contains two 500g packets of Muntons light spray dried malt + a bag of fresh hops & grain + a packet of yeast.
On reading the instructions here, it says to boil 6l of water, dd the extract, then add the hops/grain & simmer for 30mins, pour in fermenter & add either 1Kg of sugar for a pub style bitter or 3lb for something stronger & top up to 22l (with cold water).
So given that this is my first extract/dry kit, I was wondering if there was any benefit in replacing the 1Kg (or 3lb) of sugar, with another two 500g packets of dry extract, making 2Kg in total? How would this alter the ABV (2Kg of spray malt verses 1Kg spray malt & 3lb of brewing sugar?).
As for styles, I like my bitter, very much in the style of London's pride, so if anyone has an idea of how to make a similar brew, using spray malt, grain & hops, let me know

Many thanks in advance.
Darren.