Honestly, the Iron Lock is the single most tricky thing I've encountered as a single hander. The lock itself would be ok, you just bowhaul through. But, as has been said, the bridge below the lock is a problem. If it were safe, to take 2 boats through together, that would solve it (just stay on the boat and let the other boat's crew work the lock). What I ended up doing was, I waited for another boat to arrive, sweet talked them. I let them go first and asked very politely if one of their crew could hang back to get me through the lock. It worked. If there are no other boats coming, I'd have to pass the bow-line under the bridge and try and hook/grab it on the other side. Very awkward, and enough to mean I avoid going that far up the Shroppie. They could do with replacing the bridge with a split bridge like they have on the Stratford, or getting rid of the bridge.