I've dealt with clients who've gone ahead - it's a question of whether or not you can obtain a Right of Way, So no, you're not mad.
If the lane is between two properties. Then it may have a public right of way over it, despite the fact the LA don't look after it. (I mentioned the 20 years necessary to create an easement above). I'm speculating here a bit though.
I'm sure that most experienced conveyancing solicitors have dealt with such matters in the past.
Is there any way of seeing how the owners of the other houses were granted their rights of way?