Please don't fly around without at least a Pooleys it is, along with a relevant chart, the very minimum that a GA helicopter pilot ought to have with them in the cockpit. One of the many things that stops people blatting in to the Heathrow Zone, which is after all category A Airspace, without experience is the fact that the Special VFR position at Heathrow can see if you are within 25 yards of the blue line on the routes map and while they will be very understanding over minor transgressions will, if pushed, rightly tell you to turn towards the nearest boarder of the Zone and push off out of their airspace. To save any embarrassment like that, please study the Pooleys pages, carry the routes map and adhere strictly to the heights thereon. I even put the waypoints in a route on the GPS in case I suddenly need to use a route which I haven't used for a long while. This will help all the poor sods living under the routes as well as all the helicopter pilots who hope to have an industry in the future. There is a dreadful American saying " Fly Neighbourly" Of course, we prefer "Fly In A Neighbourly Fashion" but the idea is the same and knowing the routes well is part of that.