WO400 series - what information does it hold?

[josey]

From another rootschat thread, all the evidence points to a direct ancestor, William Trowsdale ca 1785 - 1844, having been in the 2nd Life Guards from 1804 to 1814
http://www.rootschat.com/forum/index.php?topic=784494.0

From the National Archives website:
Reference:   WO 400
Title:   Soldiers' Documents: The Household Cavalry
Description:   
This series contains surviving records of service for non-commissioned officers and other ranks who served in the Life Guards, the Royal Horse Guards and the Household Battalion, and whose Army service concluded in these regiments. In accordance with normal Army administrative practice of the time, the transfer of a man to another regiment meant the transfer also of his Army service record. Therefore this series does not generally contain records of service for men who served in the above regiments but who subsequently served in other regiments of the British Army.
Date:   1799-1920
Arrangement:   
The records are arranged in eight sub-series, as follows:
1st Life Guards, Series 1, 1801-1856;
1st Life Guards, Series 2, 1859-1920;
2nd Life Guards, Series 1, 1799-1856;
2nd Life Guards, Series 2, 1856-1919;
Royal Horse Guards, Series 1, 1805-1856;
Royal Horse Guards, Series 2, 1856-1886;
Royal Horse Guards, Series 3, 1886-1919;
Household Battalion, 1916-1919.

Has anyone consulted this series of records? How complete are they? Are they worth a trip to London from Yorkshire 

Thanks for any help, Josey