FT student who is working and credits-only ESA

I have a 20 year old client who is a full-time student in non-advanced education.  They receive PIP DL.  Their health condition means that they are limited in what work and how much they can do but they are managing to work every Sunday for about 5 hrs.  She is likely to meet the criteria for having a LCW.

We need to make an ESA credits only claim to establish LCW so that she can then apply for UC.

Obviously you do not need to meet the contribution conditions (or income conditions if we were looking as irESA) to apply for LCW credits - do you have to meet the ESA criteria of not being in work or are none of the criteria except LCW relevant?  Does it matter that the work is under the PW limit?

Many thanks