Iclok - your granddad and my dad were in the Munnition Column of the Royal Field Artillery which was part of the 46th (North Midland) Division which was comprised of regiments from the Danelaw part of England i.e. Lincolnshire, Nottinghamshire, Leicestershire, Derbyshire and Staffordshire. After mobilisation in August 1914 at Derby, moving headquarters onto Luton and then Bishop's Stortford, after seven months training it was ordered to France at the end of February, 1915 and was the first complete Territorial Army to arrive in any theatre of World War 1.
What a wonderful find, a bit like the first edition (now very tatty) book with it's hand coloured maps which I inherited from my dad - "The Breaking of the Hindenburg Line - The Story of the 46th (North Midland) Division" by Major R. E. Priestley, M.C.,R.E., there must only have been a limited number printed at the time, although one can now buy a reprint of Major Priestley's book.
Quote from Major Priestley's book " In less than two weeks after its arrival the Division was placed in reserve for the Battle of Neuve-Chapelle, 12th-13th March, 1915, but was not used. It received its baptism of fire at Ploegsteert, and later took over the line in front of Kemmel and Neuve-Eglise, whence its next move was to the Ypres salient. Here it settled down for nearly four months, part of which was spent in front of the notorious Hill 60". I can remember dad saying he too was on the "limbers" taking the ammunition up the line and he particularly mentioned "Hell Fire Corner" where the horses were very frightened (as I should imagine many soldiers were too) and bolted. He said that they used to try and race through there.
p.s. My uncle (his brother) volunteered at the same time as dad (September, 1914) he was in the Army Pay Corp but also a Lewis machine gunner, he was badly wounded in July 1916 on the Somme and again badly gassed and wounded at the 3rd Battle of Ypres October, 1917. Ancestry.com (or Ancestry.co.uk - can't remember which) have records for soldiers wounded in WW1 on their website (they had a free offer a year ago - November, 2008) and I was able to find his medical records and download all 17 pages of them. One can always avail oneself of Ancestry's trial offer of a 14 days trial and then cancel the subscription (before the 14 days is up of course). The WW1 medal list is also up on this website.