Upsizing a small recipe

[Redimpz]

I have recently done My first extract brew, I have to say that I am very happy with the results and i am looking at doing a larger batch of possibly 4 Gallons, (first one was only 1 Gal)
My question is would i get away with scaling up the ingredients to the amount needed for 4 Gal, but not the water, due to the size of my boiling pan.
Recipe came from YoBrew (the original recipe called for fuggles, goldings or target hops,)

500g LDME
50g Crystal malt
50g white sugar
12g cascade hops
Ale yeast
sugar for priming
method,
Make extract and malt up to 4l with water and boil for 40 mins with the hops, and a handful of hops for the last 10 minutes along with a pinch of irish moss. sieve onto the sugar and rinse with boiled water to 5l .
When i did this i was not aware of the importance of cooling so i just put the lid on and left it for 8 hours then pitched the yeast.
As I said i am very happy with it (bought worse beer in pubs) i am just wondering if it will work upsized and boiled with 6/7l then made up to 4 gal with cold water or will the higher proportions of DME and hops mess things up?
I am also considering using 1.5k LME instead of 1k of DME but I am concerned that it may be changing things too much.
Any thoughts?

[EoinMag]

The higher proportion of dme will lead to bad hop utilisation, Check out partial boil techniques, that's what you're looking to do.

[Brotherton Lad]

You could dissolve the extract and sugar first and then boil the hops either later in the same pot or concurrently in a separate pan, then add to the FV.

[evilsoc]

You should get decent results from making sure your boil is a similar gravity to what you want the finished topped off beer to be. You can add Malt extract after the boil with your top off or in the last few minutes of the boil. Google "late extract method" and read through some yank forums. I have had excellent results using this method to make malt focused beers. Beersmith has a "Add after boil" tick box that is helpful when estimating your numbers.