Rating-wise, BBG appears to be the easiest of the steep lines at the crag. However, the first 4 clips of this beast will leave you wondering if you should have tried Land's End or even Shoreline instead since they only have a couple of hard moves... The book give BBG 11c, I feel like it deserves solid 11d/12a based on its consistent difficulty.
Start by not laughing at the very low first bolt. Some people peel off before getting anywhere near the 2nd one... Once you figure out the burly start, keep pulling big moves between OK holds hidden in a pile of sloppy cobbles. A big undercling in the roof of the mini-cave provides a welcome rest before you launch into the upper section. While not as steep, it forces you to stem on crusty feet and lieback a crack feature, providing plenty of opportunities for air...
BBG sits between the steepest line at Shoreline (name unknown) and the crag's namesake route.
Walk across the 4th class traverse with the fixed line to the base of the big trough that separates the ridiculously steep 12/13 lines from the more reasonable routes.
Or refer to Tristan's great topo here
7 bolts to chain anchors.