The book was written before science fiction was a true genre - hence my fascination with it and my unremitting requests to borrow it (from someone who is unwilling to lend out books becuaes 'they never come back')
I borrowed this book and then lost it. I read the first chapter prior. I must replace it but... searching for it is very difficult because I believe the character was called Eric(k) and Monty Python is swamping my search results.
He lived in a cave, lost his arm(maybe leg) and fell in mud so didn't die and regenerated his limb.