In reply to Pommie574:
skip the bivi, set off pre dawn. Don't cross at dunmail, but about 1 km down the road ( and 100m lower MASL) there is pub for an energy boost. It can't be much over 40-45km in total?
If you bivi/camp the challenge will be carrying the weight and choosing your book for the evening. If you push it in a day the challenge will be moving well on your feet and good route selection between Dunmail area and Esk Hause, trying to balance height loss, contouring, shortest route etc.