Can you shed any light?

This is a recent email from a reader ( Phill ) who asked for some help. I have no idea what this is so I have passed the question on to the blog, hopefully someone may know the answer.

"I wonder if you can help me.

I have recently purchased a very specialised Machin and castles collection.

There is one Machin item I do not recognise - I have attached a scan - It appears to be a sheet of the first self adhesives (There is no self adhesive backing on the stamps, and no gum on the back of the sheet either)

I guess it is either a sample type reference sheet of the self adhesive issue - or a sheet produced by favour of the postal stationary dies? 

Can you shed any light?"