David Seeney of the Excalibur Walking Group in Hereford (LDWA affiliates) has passed on details of a local 15 or 20ml challenge walk starting from Lea Village Hall in south-east Herefordshire.
Details here -

http://www.ariconium.org/challenge

Although it's billed as a charity walk, it's the proceeds that go to charity rather than it being a sponsored walk.