I think that some of the sentences are able to mix the word classes and still make sense. This is shown when Orwell writes ‘I shall double the final figure in order to arrive at the complete amount.’

This can be rewritten as ‘The final figure shall be doubled in order to arrive at the complete amount.’ However, I think that this takes away the feeling that the author is involved.

 

Original:

And if our book consumption remains as low as it has been, at least let us admit that is because reading is a less exciting pastime than going to the dogs, the pictures or the pub, and not because books, whether bought or borrowed, are too expensive.

 

Simplified:

Our book consumption remains low. At least let us admit that it is because reading is a less exciting pastime. Not because books are too expensive.