If I need to change my P60, do I really need to get hold of another form?

No. So long as all pertinent details are included, HMRC will accept notification of changes to a P60 return by means of a letter. Other HMRC forms affected by the change to the P60, such as a worker's self assessment return, may need to be updated by means of submitting a revised return. Please contact your local tax office for advice.