I don't find 82% to be that high. Based on the calculations that Hopville.com's recipe calculator produces for my brews, I get usually get between 80 and 86% for brews based mainly on British pale malt, mashing at 66-68C for 1.5-2 hrs, and 75% or a bit more if there is a good proportion of other stuff like oat flakes or roasted malts. I also use a grain bag, mashing in a boiler. My OG is always higher than the calculator estimates for the recipe. I haven't actually calulated the amount empirically myself though. 55% would be very low indeed. From your description I would expect 82% or thereabouts, sounds fine to me.
I just fed your grain bill (based on 7 1/2 lbs Great Western Premium 2-Row Malt and 1 1/2 lbs American Crystal 60L) into hopville.com's beer calculus and it estimates it would take 89% efficiency to get an OG of 1.080, which really does sound very high. Clearly it is calculating differently from the one you use!