I have over 24 years experience in teaching and assessing at British Universities. My main focus for theaching is Computing/Technology and Business Computing programmes, I only operate on a one to one basis. I usually ask the student to send me their assessment specification and a copy of their draft work.
I will not write any assessments for anyone.
One of the main questions and taks I encounter with students is on grammar, punctuation as well as the actual content of the assessment the student is writing, to ensure that the work meets the learning outcomes of the specification that the student has to submit. If the draft work does not yet do this I can advise on what is missing and how it relates to what is required.

There will obviously be the questions that are raised by students on theior draft work, and many sessions are largely student led and student focussed.
My experience is working with both undergraduate and postgraduate students, I have no expereince of A level or other pre-University studies.
I do have a post grad Certificate in Teaching English as a Second Language, and I am experienced in working with students whose first langauge is not English.