The easiest way to get the umlaut is by using Insert Symbol in Word etc. Otherwise you can use the number pad for individual letters: Alt148 should give you ö, for instance.
Well, you could try the Imperial War Museum, the Commonwealth War Graves Commission (if he was killed in the Great War) or there might be regimental records.
Apologies if this has already been covered elsewhere, but I've just discovered "Tommy" by Richard Holmes, and so far it's as good as everything else he's done. It's £8.99, but Waterstone's have it as part of their current 3 for 2 offer.
Something else which people might find useful is...
Smiler Marshall, seen in many WW1 interviews, has died at 108.
There was an obit in the Telegraph - here's a link which may or may not work!
http://portal.telegraph.co.uk/news/main.jhtml?xml=/news/2005/05/20/nobit20.xml
Among the best books on the Somme battle and the Accrington Pals' part in it is "The First Day on the Somme" by Martin Middlebrook.
One of the early Biggles books, "Biggles, Pioneer Air Fighter", includes a story "The Zone Call" which explains how the air to ground wireless system worked