Information on WW1 records

[harveyh]

I wonder if anyone could point me in the right direction .   My Grandfather enlisted on 9th Dec 1915, in the Royal Engineers as he worked on the Railway.
His WW1 record shows he was Home 29.9.16 to 12.5.17  and BEF 13.5.17 does anyone know what BEF means? The biggest puzzler is a photograph of him wearing a Scottish attire , Kilt and scocks. There was a bit of a rumble that he did a runner and was put in the Scotts regiment but I can't find how to substantiate this.
His name was Alfred Pearce and date of birth 24/11/1881. Regiment number 201563  WR 260312
Than you for reading

[Christine53]

BEF = British Expeditionary Force.

Some info here :

https://en.wikipedia.org/wiki/British_Expeditionary_Force_(World_War_I)
https://en.wikipedia.org/wiki/British_Expeditionary_Force_order_of_battle_(1914)

[harveyh]

 Thank you so much for replying,  never thought of that! I will have a look to see if I can access those records somewhere.