Aye Smudge,
Your engine woes seem worse than mine, so I'm sending some sympathy along with this!

As for sheds (back 'on message')

, sleepers, 100mm or 150mm blocks all good. Bed into sand if needed.
BEFORE ERECTING SHED/LAYING FLOOR ON TOP, LAY A STRIP OF 100mm DAMP COURSE/HEAVY ROOFING FELT DOWN AND THEN SIT THE WOODEN BITS ON TOP. STOPS THE CAPILIARY ACTION OF THE WATER COMING UP THROUGH THE BLOCKS AND ROTTING THE ARSE OUT OF THE FRAME/FLOOR!
One reason why 30 + year old timber frame houses rot out the bottom of the frame, due to 'jerry' builders!

Allow air-space beneath floor, but watch out for 'longtails' and other vermin taking up residence!

Off to sheet alley and see if Sally will co-operate tomorrow, cam chain timing marks at the back of the alternator! Bah! Humbug! Grump!

Slainte, Bill.
