Car milage claimed against tax?

From april 2003 to april 2004 I was a Homecarer but my employer never5 told me I could claim an allowance. I was certainly entitled to. Can I still claim it..? There are several of us disgruntled emloyees who were victims of a disreputable firm who have since gone bust. I have all my P60's, some rotas and a few wage slips