In reply to JackM92:
From what I remember: Once you've done the initial sketchy slab solo you end up just below the metal spike. It's just out of reach but you can take a sling and flick it over the spike from here, rather than doing one or two extra moves to reach it comfortably.
That's how I interpreted 'lasso the spike from below', as it says in the guidebook. The UKC description is the first I've heard of lassoing the spike from the route next door. I don't see the difference between this and pre-clipping it on abseil tbh. Nothing wrong with doing it this way, of course, but call it what it is, ie not really leading the route!
I think it's E4 to lead. Half top-rope half leading it feels more like sport climbing (the top half is bolted) and is maybe 6c? It's a nice route either way you do it, totally different character depending on your chosen method, obviously.