WIR History: A really good site gives list of various regiments and active service with wealth of other info (alas nothing about personal experiences)
Check out the Slave Purchase link. Slave Purchase

The National Archives of the United Kingdom Home page of National Archives just type WIR [in full] in their catalogue search. This will only give you the reference code of documents. Although you can search the on-line docs but you have to pay to view them.

An example from Archives:

WO Records created or inherited by the War Office, Armed Forces, Judge Advocate General, and related bodies
Division within WO Records of the Royal Chelsea and Kilmainham Hospitals
WO 97 Royal Hospital Chelsea: Soldiers Service Documents
Subseries within WO 97 1760-1854: discharge papers arranged by regiment, but each described at item level. (WO 97/1-1271)
WO 97/1228 Royal Artillery: Foa - Fyf


Record Summary
Scope and content MARTIN FRENCH
Born Africa
Served in West India Regiment; Royal Artillery
Discharged aged 23
Covering dates 1845-1849

Held by The National Archives, Kew