Hi Mandy,
I'm glad I helped a little.
Soldiers who served with the Labour Corp are very difficult to trace due to the large number of Companies and varied jobs they undertook.
This is interesting:
The Labour Corps is formed Formed in January 1917, the Corps grew to some 389,900 men (more than 10% of the total size of the Army) by the Armistice. Of this total, around 175,000 were working in the United Kingdom and the rest in the theatres of war. The Corps was manned by officers and other ranks who had been medically rated below the "A1" condition needed for front line service. Many were returned wounded. Labour Corps units were often deployed for work within range of the enemy guns, sometimes for lengthy periods. In April 1917, a number of infantry battalions were transferred to the Corps. The Labour Corps absorbed the 28 ASC Labour Companies between February and June 1917.
It's possible that Robert was in one of the pioneer Battalions (due to his mining experience) part of the Yorkshire Light Infantry prior to 1917 and when the Labour Corp was formed in 1917 transferred from the Yorkshire Light Infantry. It's also possible due to wounds received he wasn't A1 fit to rejoin his infantry Battalion and was then transferred the Labour Corp.
The problem is without his service records it's very difficult to work out.
Try and post on this forum:
Forums - Royal Pioneer Corps & Royal Pioneer Association
http://www.royalpioneercorps.co.ukThis forum is run by a very knowledgable man who maybe able to help further.
I would be very interested if you find any further information.
Good luck.
Adrian