As regards medals (this is broadly speaking to avoid the pedants - you can get exact details from Long Long Trail
1. A soldier got the 1914 star if he was in a battle zone in 1914
2. A soldier got 1915 star if he was in a battle zone in 1915
3. A soldier got Victory Medal and War Medal if he served abroad during the war at any time
Therefore it was important that the army kept a record of when a man served in a war zone. As you know 14/6/15 is when he landed in Gallipoli
There seems to be some evidence that he landed somewhere in 1914, if he did he would have the 1914 star. Normally the MIC only records the first entry into a war zone.
You should do a bit of research on Labour Corps, basically as the war wound down, men were transferred to Labour Corps to do "useful" work while waiting demob.
Do not be put off by the destruction of the records, with his details someone can check. Look upon it as 1 in 3 surviving.
Even if you cannot get the service record, as long as you can get the war diary it will give you a day by day account of what the battalion was doin.
A quick read of the East Lancs info on Long Long Trail show that
6th (Service) Battalion
Formed at Preston in August 1914 as part of K1 and attached to 38th Brigade, 13th (Western) Division. Moved to Lucknow Barracks, Tidworth but by January 1915 was in billets in Winchester. Moved to Alma Barracks, Blackdown (Aldershot) in February 1915.
Sailed from Avonmouth on 16 June 1915 and landed on Gallipoli 7 July 1915.I suspect that your June date may be when the battalion arrived in Alexandria or Mudros before going on to Gallipoli.
East Lancs enlistment numbers and dates are here
http://armyservicenumbers.blogspot.com/2009/06/east-lancashire-regiment-1st-2nd.htmlYour man's number points to Autumn 1914 enlistment