author of a 1940s children's book about 2 children's voyag

Question:

Anyone know the title/author of a 1940s children's book about 2 children's voyage in a coracle down a river???

Published sometime around 1940. The river was possibly on the Welsh/English border. I'm looking for this for a friend who just can't remember the title or author, but says it could have been part of a series called 'Getahead Books'. Any suggestions much appreciated.

Additional Details

2 weeks ago
Should have said - it's not an Arthur Ransome - that would be toooooo easy :)

2 weeks ago
Great reponses - but nope, it's not Bevis, and nope it't not the Green Knowe series. Just checked them both out. Green Knowe was closest, except for the ghosts and the river trip was by canoe. The one I'm after was definitely a trip by coracle. Will check out the website suggested. Thank you one and all!! Keep 'em coming.

Best Answer - Chosen by Asker: 2 weeks ago
Should have said - it's not an Arthur Ransome - that would be toooooo easy :)