I'd agree with Genghis that SkyDemon is an excellent flight planning and navigational tool. You can also print out the route you've planned so if the GPS goes tits-up en route you've still got a purple line on a topo to follow.
One (controversial) British peculiarity is QFE, the altimeter setting which gives a zero reading on the ground at an airfield. Many pilots disregard this setting and fly QNH throughout, which you'll be familiar with.