Here is a list of past treks and long distance walking adventures:
2003 South Downs Way - Extended route, 116 miles over 8 days.
2005-8 South West Coast Path - 630 miles in 6 one-week sections.
2006 Hadrian's Wall - Extended to Tynemouth, 102 miles over 6 days.
2007 West Highland Way - 126 miles, including Ben Lomand and Ben Nevis, over 8 days.
2008 Sarum Way (modified) - 32 miles over 2 days.
2008 Brecon Beacons Way (modified) - 103 miles over 7 days.
2009 Avon Valley Path - 34 miles in one day (overnight).
2009 Lake District Tour - 39 peaks >2000m and 7 lesser peaks over 8 days.
2009 Dartmoor tour - 28 tors over 2 days.
2009 John o'Groats to Land's End - 1200 miles over 84 days.
2010 Wayfarer's Walk - 70 miles over 4 days.
2010 Wainwright Coast-to-Coast - Extended route, 217 miles over 17 days.
2010 & 2011 White Horse Walk - 100km (62.5 miles) over 3 days.
2011 Cairngorms - 20 miles over 2 days.
2011 GR221 (Majorca) - 76 miles over 10 days.
2012 GR131 (Tenerife and La Palma) - 73 miles over 8 days.
2013 White Horse Walk - 100km (62.5 miles), 20 hrs 28min in a continuous walk.
2013 Test Way - 44 miles in 3 days.
Lots of other single-day and multi-day walks in England, Wales, Scotland, Eire, Austria, Norway and Madeira.
Long distance paths that I would like to add to my list include the HRP Pyrenean traverse, the GR20 in Corsica and the Cape Wrath trail in Scotland.