Self Assessment for 12yr old

ANGLICANPAT

My 12 yr old grandchild needs to pay a small amount of  CGT for 20/21.  I have got an accountant  sorted to later work out the figures etc, but  he told me he needs child to have a UTR and to ring  HMRC. After  Looooooong  wait , I got through to HMRC , explained the situation and was told no problem , send in  form SA1   - which is essentially for people needing to do an assessment who aren't in business. This form could also  be used to give child  a  UTR to then go ahead with. SA.

 Realize now , looking at form ,  that its questions are written in the  first person 
 Im presuming that its to be answered in childs name  as its the info on the child  that they need to  get, to raise a UTR .albeit the form only asks for name ,address , dob, type of  tax you owe, and a signature .    It does ask for  a NINO  which of course  child doesnt have, but theres a box to explain why you think you dont need a NINO  which I can write in highlighting the age..  

Then the signature box  would have to be signed by me I suppose  with my contact number . It bothers me that theres no  requirement or space  for a second  set of details for me filling in  on behalf of the child. 
My question is,   do you reckon I've been told  the right form  to fill in ?    If it makes a difference , the CGT is on shares sold in an investment  in a bare trust created by me as grandparent  in childs name .  Maybe its only a parent who can apply for a UTR for their child  though ?

Just thought someone on here might know please , before I embark on another  HMR phone marathon. 

tacpot12

I don't know the answer for certain, but if it is not too much trouble to get the parent to sign the form, I would think that this would be better/more correct this to do, so that parent is taking responsibility for their child paying tax if they need to.