This explanation from the Times makes much more sense.
The puzzle is basically looking for the sums of all subphrase of the text that are clearly pence.
Hence 2 pounds contains the phrases "2 pounds", "2 p" and "p" and it's looking for the sum of all these. Not sure where the BBC got all that stuff about 47 and 7 from - that doesn't make any logical sense.
However, it still doesn't seem fair that the question doesn't seem to include any hint of what it's looking for. A few more words were all that was required eg "Add all the pence contained in the following".
Rephrased to make it clearer, it could have actually been a reasonably good puzzle.