The first one could be puzzled out, the second one I worked out about one sentence in (although my intial thought was then to look inside the cistern, rather than the back) and the third... well it would be bloody obvious to me that it would rearrange to SINK not INKS and "the primary letters" struck me as being the first of each paragraph. I couldn't get why you said they wouldn't know which letters they are...
The reason I'd get stuck was because kailyard doesn't exist as a word in my vocabulary (neither does the concept of a kitchen garden exist to me outside of stately homes) - but I figure that these are things your friends would know about.
And without seeing your kitchen ceiling I don't know how obvious it is that it's a false ceiling...
But yeah, I'd consider it a fairly easy 60 quid *shrugs*
