the real problem is pete how do you put sides on a shed when they are only 30mm apart - totally impractical really!!! not a chance of boarding and putting the loglap on before you build it as too heavy so realistic gap will be 18 inchesWith a 30mm gap, I'm sure you can come up with some ingenious way of linking the the two sheds via double doors, say? Close em, 2 sheds. Open em, 1 shed.
And yes, shed logs (shed porn) are all the rage these days. Do it!