Hi Chrisy

Whilst the Instructor course can and will be interpreted slightly differently by individual instructors and their respective centres, the core of what you will be doing will be the same. Not only will your operating ability be assessed to a higher standard you will also work on a range of topics which include but are not limited to:
Theory - Health and Safety law and how it applies to the training of operators. This will also include reference to and teaching of the relevant regulations produced by HSE, Provision and use of Work Equipment Regs 98 / Lifting Operations and Lifting Equipment Regs 98 / Approved Code of Practice L117: Rider Operated Lift trucks Operator Training etc.
Practical - Practical and in-class lesson planning, preparation, rehearsal and delivery. Report Writing. Principles of instruction. The use of visual aids. The basic operating Skills Test.

This is by no means a definitive list of subject matter, but should give you an idea of the course.

In addition all of the reference material I have listed is available free to download from the HSE website so you can get an idea of the sort of information contained.

Hope all this helps, all the very best for the course and good luck and enjoy.