In reply to Stuart the postie:
Stuart managed to unearth this description for Hogwarts Express, i will put it here just in case anyone else is interested, it sounds quite good, i hope i'm not prone to exageration!
The Brack: Hogwarts Express 125m Vl7 Andy Clarke, Frank Yeoman, Jan 4 02
Stella mixed climbing with great exposure. Climbs the right edge of the wall, right of Great central groove/Resolution,finishing up the oblique tapered fault.
(much verglas on this ascent) start at the toe of the wall.
1.40m climb up to an obvious line trending up and right(as for Resolution) continue right climbing a short wall, to belay below a steep wall on the edge.
2.15m climb steeply above the belay into an overhung niche, move left (bold) to a thin turf ledge, then more easily to a turf ledge.
3. 30m Traverse left a short distance then tackle the wall direct, aiming for a vague crack in it's upper half, move right crossing an iced slab to reach a ledge below the oblique tapered fault of Mainline.
4. Climb the fault, when it overhangs move onto the edge, to easy ground below the final wall.
5. 10m The steep thinly iced wall above(as for Mainline summer).
Regarding the grade of Purple Blaze, i'm happy with what ever the consensus is, you must have a good idea.