This M is in a field just south of Carlisle.
Imagine! Back in 2003, some bloke with a tractor had the foresight to know I was going to embark on this pointless project and went round and round in a field until he'd made a stylised "M" that could be seen from the air! Thank you, Man on tractor. A packet of M and M's is winging its way through the postal system even as I type this.
Finding those two letters in such a short space of time has really given me a boost. Suddenly the upper case alphabet has only 8 letters to go, and one of them is the letter "I" which will be easy. I suspect that "K" and "R" will be the hardest, but we shall see...