Hello John,
Crowhurst is a good Sussex name

Here is a breakdown of his service:
Joseph Crowhurst, 124448, Royal Field Artillery
Attested at Uckfield 11th December 1915
Joined at Woolwich 14th April 1916 (No. 4 Depot RFA) as Driver
Took trade test, appointed Wheeler and posted to 20th Reserve Battery on 24th April 1916
Overseas to France 2nd May 1916 (extremely fast posting!!!)
From 6th May 1916 to 27th July 1917, when he went on leave, he was with 32nd Divisional Artillery: Divisional Ammunition Column; “C” Battery, 168 Brigade; a spell attached to IOM Workshop(?) and then to Divisional HQ.
He returned to the DAC on 6th August 1917 until a further 2 week period of leave to the UK commencing 14th September 1918.
The next bit is unreadable and there appears to be a couple of months missing, but he was with the Army of Occupation in Bonn on 16th April 1919.
Dispersed at Crystal Palace 21st April 1919 and transferred to Class Z Reserve.
He was awarded the British War and Victory Medals.
There are no health problems reported on his discharge document.
Phil