I agree that everyone has their own way of doing things. But to brew the clone, you need to open a Fuller's, pour it in a glass, smell it, taste it, feel it, look at it, write down what you think...are you getting toffee, caramel, nuts, roast, toast, dark fruit...is it crystal clear with hints of ruby red or more biscuit brown, are the hops forward or non-existent, how does the bitterness balance the grain bill...etc. etc.
Then figure out how YOU need to get there. Recipes are a fine starting place, but whoever wrote them never brewed with your equipment, or grains or fermentation practices...and they don't have your palate. Your perception of the beer may not be the same as the author's.
Regarding the chocolate malt that Fuller's lists on their website as one of their ingredients: Every ounce of chocolate malt that gets used is a lot more ounces of crystal malt that doesn't need to be there. The chocolate obviously pushes the color, but it can also help keep the perceived sweetness down and add a bit of drinkability. My .02
Good luck!