If you or your partner want to up things a little further, I'd say invest a little (under £50) in a coffee grinder and switch to whole bean. I believe burr grinders are the way to go and electric is a lot easier. You can adjust your grind according to the brewing method.
It's less of a step up from going instant to ground, but you'll be able to pick up the tasting notes more clearly, and if you drink it regularly it's a fairly small investment. Whole bean itself shouldn't cost any more than buying it as ground.