You need this seatpost. Very tall, and very laid back to get your saddle back, and still rotates through a broad range which is impt. to level a Brooks saddle.
'
http://www.wallbike.com/seatposts/uno374.html

Note that this is special from the kalloy unos in qpb catalogue. Wallingford has them made to special specs, so only get the uno 374. If its still not long enough, look at MTB posts.