Hi PBR Street Gang
You can complete the form which ever way you find comfortable, I nearly always complete the form as if I was the claimant then at the end under further information state i completed the form and reason why claimant was not able to complete the form, I usually attach my works business card.
I always get the claimant to sign even if it is just a squiggle or a cross.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems