Entire to Luxborough, Summersetshire from London in 1771, with a manuscript Harwood London Receiver ?

The entire below was sent from London to Luxborough near Dunster in November 1771.  It has a triangular London Penny Post Paid handstamp, a red manuscript "Harwood", a London bishop mark for 17th November and manuscript "4" and a smaller "5" for postage.

"Harwood" may be the name of the London receiver, though I cannot find a "Harwood" in Hugh Feldman's "Letter Receivers of London".  The sender has paid 1d for the London local post (hence the triangular "Penny Post Paid" mark), and the General Post to Dunster would have been 4d for over 80 miles.  The smaller "5" could be the total charge including local delivery to Luxborough.
 

Eighteenth Century London Receivers

In the 1700s a number of the Letter Receivers in London had their own handstamps.  Here are a couple of examples, the first going to Ilminster.  The entire is undated;  based on the London bishop mark and 8d postal charge it must date from 1713 to 1784.  It has an "AR" in a circle receiver's mark which looks to be for Abel Roper who was a bookseller in Fleet Street from 1688 to 1726, so the entire would date from 1713 to 1726.

My second example is from London to Langport and is again undated.  It has an "RB" in a circle receiver's mark, which is from Richard Brunton who was a receiver at Mount Street by Berkeley Square from 1768 to 1783.  His "RB" in a circle mark is known in use from 1770 to 1772.