Lynton manuscript "No 1" in Minehead Penny Post

According to Oxley "The English Provincial Local Posts 1765-1840", Minehead's Penny Post was established in 1832 with three Receiving Houses at Holnicote, Porlock and Lynton (Minehead was a sub-office of Taunton).  Unboxed Receiving House cancels for No.2 (Porlock) and No.3 (Holnicote ?) are known, but a "No.1" cancel is not known to have been issued for Lynton.

The wrapper below, from Wellington to Lynton, has a rare manuscript "No 1" on the front apparently for the Lynton Receiving House.

It also has a partial blurred small straight-line cancel on the reverse.  Any ideas ?  From a distance it might just be "MINEHEAD" ??

The wrapper has been sent "Free", endorsed on 4th August 1837.  It is signed by "E Ayshford Sanford".  Edward Ayshford Sanford was the MP for Somerset from 1830-1841 and lived in Nynehead Court.  Despite the "Free" endorsement it should still have been charged 1d for the Penny Post as the "Free" endorsement was only for the General Post.