As others have noted there are a few MGH booking classes which don't earn.
For avios and TP earning in economy on MH:
- L, V, S, K, M, Y, B, and H earn avios and TPs
- N, Q, O, and G earn nothing
For avios and TP earning in business on MH:
- J, C, D, and Z earn avios and TPs
- I earns nothing
For avios and TP earning in first on MH:
- F and A ean avios and TPs
- P earns nothing
This post on a blog may give you a method of finding boking classes on the MH webiste when booking
http://flystaytravel.com/how-to-find...lines-flights/
It has been raised before as well in these threads:
http://www.flyertalk.com/forum/briti...-tp-avios.html
http://www.flyertalk.com/forum/briti...re-i-book.html
http://www.flyertalk.com/forum/briti...-avios-tp.html
http://www.flyertalk.com/forum/briti...a-flights.html