In the plymouth area, I've found art workshops at the College of art that would help with illustration development. such as the illustration cafe. for these classes, you would need basic skills in visualy communicating ideas and words through drawings. I feel i am already confident in this type of illustration and have the required skills.
If I were to set up a portfolio of my work, i would gather all my images into one collection and organise them into subjects. Such as sculptures and illustrations, then into further categories such as animal sculptures and still life pieces.