“It was not until June, 1917, that, armed with Field Artillery equipment, they proceeded to France as part of the 126th Army Field Brigade”
My understanding is that Field Artillery refers to the fully-mobile 13- and 18- pounder wheeled light guns operated by the RFA & RHA, whereas the 4.5” to 8” howitzers were the heavy, often dug-in guns manned by the Siege Batteries of the RGA.
Regards,
JMB