St Austell Proper Job Recipe

So i am going to attempt a light quite fruity hoppy beer similar to that of one of my favourite ales proper job by St. Austell.

I was looking into the recipe for this beer and it says that the grain they use is pale malt, maris otter. however i have typed all the data into beersmith and its telling me to use a substantial amount of grain to acheive my OG / FG and i assume its becasue of the low SRM of pale malt. Does anybody know if other malts are used in this brew or how i can increase sugars without getting a truck load of pale malt in whilst still mainatining a good beer. I want to stay away from crystal malt as it gives me a sweet smell / taste which is not how this beer tastes.

any comments from my fellow brewers would be much appreciated.

Hi,
I share your affinity to St. Austell's Proper job, great IPA! I notice there are unfortunately no reactions on your post.
However, how far did you come in your attempts composing a recipe, perhaps even brewing it?
Regards,
Slurk