What to charge for 'call-outs'?

My new self-employing job (I.T. Consultancy) is going to entail callouts from time to time. Which means I'll need to factor in costs for travel expenses .. does anyone know what the standard rate is per mile?


Also, should I charge an extra standard 'callout charge', like maybe €25 for the site visit (irrespective of distance and time allowance)?


Fergal #.